Update libsrtp to version 2.0

srtp/CHANGES

-Changelog
-
-1.5.2
- 
-  Autoconf checks for libz and libdl for buildroot support.
-
-  Pull request 96 - Include config.h to get inline on Windows.
-
-  Pull request 93 - Don't include AES-192 when compiling against BoringSSL.
-
-1.5.1
-
-  Pull request 95 - Additional header check from Chromium
-
-  Pull request 94 - Add missing copyright headers. 
-
-  Pull request 90 - Fix out-of-source tree builds.
-
-  Pull request 89 - Introduce little endian RISC support
-
-  Pull request 86 - Add support for cross-compiling the shared library for Windows and OS X
-
-  Pull request 85 - Add -f <pcap filter> option to rtp_decoder
-
-  Pull request 84 - Avoid problems due to unsafe macros
-
-  Pull request 82 - Align the AES ICM nonce
-
-  Pull request 80 - Take advantage of base64 conversion in testapps
-
-  Pull request 75 - Cleanup: miscellaneous cleanup of initial OpenSSL AES support
-
-  Pull request 74 - Allow testing with pcap file or capture - Issue #45
-
-  Other trivial fixes are included as well.  Please see github for details.
-
-1.5.0
- 
-  Add support for using OpenSSL crypto using the --enable-openssl 
-  option.
-
-  Add support for AES-GCM crypto suites. 
-
-  Add support for pkg_config.
-
-  Add user data API to allow user to associate additional data with a 
-  SRTP context.
-
-  This release also includes a variety of bug fixes, which can be 
-  viewed at: https://github.com/cisco/libsrtp/commits/master
-
-  Note: The change log was not maintained between versions 1.3.20 and
-        1.4.5.
-
-1.3.20
-
-  Lots of changes.  Thanks to Jeff Chan for catching a memory leak and
-  helping track down the endian issues with the SSRCs.
-
-1.3.8
-
-  This is an interim release.  Several little-endian bugs were identified
-  and fixed; this means that we can use intel/linux for development again.
-
-  Cleaned up sha1 and hmac code significantly, got rid of some excess
-  functions and properly documented the fuctions in the .h files.
-
-  Eliminated some vestigial files.
-
-  There is a SIGBUS error in the AES encrypt function on sparc
-  (observed on both solaris and openbsd) with gcc 2.95.  Was unable to
-  find bad pointer anywhere, so I'm wondering if it isn't a compiler
-  problem (there's a known problem whose profile it fits).  It doesn't
-  appear on any other platform, even in the cipher_driver stress
-  tests.
-
-  Planned changes
-
-  Change interface to nonces (xtd_seq_num_t) so that it uses
-  network byte ordering, and is consistent with other arguments.
-
-
-1.3.6 
-
-  Changed /dev/random (in configure.in and crypto/rng/rand_source.c) to
-  /dev/urandom; the latter is non-blocking on all known platforms (which 
-  corrects some programs that seem to hang) and is actually present on 
-  Open BSD (unlike /dev/random, which only works in the presence of 
-  hardware supported random number generation).
-
-  Added machine/types.h case in include/integers.h.
-
-1.3.5
-
-  Removing srtp_t::template and stream_clone().
-
-  Adding a new policy structure, which will reflect a complete SRTP
-  policy (including SRTCP).
-
-  This version is *incomplete* and will undergo more changes.  It is
-  provided only as a basis for discussion.
-
-1.3.4
-
-   Removed tmmh.c and tmmh.h, which implemented version one of TMMH.
-
-   Changed srtp_get_trailer_length() to act on streams rather than
-   sessions, and documented the macro SRTP_MAX_TRAILER_LEN, which should
-   usually be used rather than that function.
-
-   Removed 'salt' from cipher input. 
-
-   Changed rdbx to use err.h error codes.
-
-   Changed malloc() and free() to xalloc() and xfree; these functions
-   are defined in crypto/kernel/alloc.c and declared in 
-   include/alloc.h.
-
-   Added 'output' functions to cipher, in addition to 'encrypt'
-   functions.  It is no longer necessary to zeroize a buffer before
-   encrypting in order to get keystream.
-
-   Changed octet_string_hex_string() so that "times two" isn't needed
-   in its input.
-
-   Added crypto_kernel_init() prior to command-line parsing, so that
-   kernel can be passed command-line arguments, such as "-d
-   debug_module".  This was done to for the applications
-   test/srtp-driver, test/kernel-driver, and test/ust-driver.
-
-   Improved srtp_init_aes_128_prf - wrote key derivation function
-   (srtp_kdf_t).
-
-   Add the tag_len as an argument to the auth_compute() function, but
-   not the corresponding macro.  This change allows the tag length for
-   a given auth func to be set to different values at initialization
-   time.  Previously, the structure auth_t contained the
-   output_length, but that value was inaccessible from hmac_compute()
-   and other functions.
-
-   Re-named files from a-b.c to a_b.c. in order to help portability.
-
-   Re-named rijndael to aes (or aes_128 as appropriate).
-
-
-1.2.1 
-
-  Changes so that 1.2.0 compiles on cygwin-win2k.
-
-  Added better error reporting system.  If syslog is present on the
-  OS, then it is used.
-
-
-1.2.0 Many improvements and additions, and a fex fixes
-
-   Fixed endian issues in RTP header construction in the function
-   rtp_sendto() in srtp/rtp.c.
-
-   Implemented RIJNDAEL decryption operation, adding the functions
-   rijndael_decrypt() and rijndael_expand_decryption_key().  Also
-   re-named rijndael_expand_key() to rijndael_expand_encryption_key()
-   for consistency.
-
-   Implemented random number source using /dev/random, in the files
-   crypto/rng/rand_source.c and include/rand_source.h.
-
-   Added index check to SEAL cipher (only values less than 2^32 are
-   allowed)
-
-   Added test case for null_auth authentication function.
-
-   Added a timing test which tests the effect of CPU cache thrash on
-   cipher throughput.  The test is done by the function
-   cipher_test_throughput_array(); the function
-   cipher_array_alloc_init() creates an array of ciphers for use in
-   this test.  This test can be accessed by using the -a flag to
-   the application cipher-driver in the test subdirectory.
- 
-   Added argument processing to ust-driver.c, and added that app to
-   the 'runtest' target in Makefile.in.
-
-   A minor auth_t API change: last argument of auth_init() eliminated.
-
-
-1.0.6 A small but important fix
-
-   Fixed srtp_init_aes_128_prf() by adding octet_string_set_to_zero()
-   after buffer allocation.
-
-   Eliminated references to no-longer-existing variables in debugging
-   code in srtp/srtp.c.  This fixes the compilation failure that
-   occured when using PRINT_DEBUG in that file.
-
-   Corrected spelling of Richard Priestley's name in credits.  Sorry
-   Richard!
-
-
-1.0.5 Many little fixes
-
-   Fixed octet_string_set_to_zero(), which was writing one
-   more zero octet than it should.  This bug caused srtp_protect()
-   and srtp_unprotect() to overwrite the byte that followed the
-   srtp packet.
-
-   Changed sizeof(uint32_t) to srtp_get_trailer_length() in
-   srtp-driver.c.  This is just defensive coding.
-
-   Added NULL check to malloc in srtp_alloc().
-
-
-1.0.4 Many minor fixes and two big ones (thanks for the bug reports!)
-
-   Removed 'ssrc' from the srtp_init_aes_128_prf() function argument
-   list.  This is so that applications which do not a priori know the
-   ssrc which they will be receiving can still use libsrtp.  Now the
-   SSRC value is gleaned from the rtp header and exored into the
-   counter mode offset in the srtp_protect() and srtp_unprotect()
-   functions, if that cipher is used.  This change cascaed through
-   many other functions, including srtp_init_from_hex(),
-   srtp_sender_init() and srtp_receiver_init() in rtp.c, and also
-   changing the CLI to test/rtpw.  In the future, another function
-   call will be added to the library that enables multiple ssrc/key
-   pairs to be installed into the same srtp session, so that libsrtp
-   works with multiple srtp senders.  For now, this functionality is
-   lacking.
-
-   Removed the GDOI interface to the rtpw demo program.  This will be
-   added again at a later date, after the SRTP and GDOI distributions
-   stabilize.  For now, I've left in the GDOI #defines and autoconf
-   definitions so that they'll be in place when needed.
-
-   Updated tmmhv2_compute() so that it didn't assume any particular
-   alginment of the output tag.
-
-   Changed bit field variables in srtp.h to unsigned char from
-   unsigned int in order to avoid a potential endianness issue.
-
-   Fixed rdbx_estimate_index() to handle all input cases.  This solves
-   the now notorious "abaft" bug in the rtpw demo app on linux/intel,
-   in which spurious replay protection failures happen after that word
-   is received.
-
-   Added ntohs(hdr->seq) to srtp_protect and srtp_unprotect, removed
-   from rijndael_icm_set_segment().
-
-   Added error checking and handling to srtp_sender_init() and
-   srtp_receiver_init().
-
-   Changed srtp_alloc() so that it does what you'd expect: allocate an
-   srtp_ctx_t structure.  This hides the library internals.
-
-
-1.0.1   Many minor fixes
-
-   Added cipher_driver_buffer_test(...) to test/cipher-driver.c.  This
-   function checks that the byte-buffering functions used by a cipher
-   are correct.
-
-   Fixed SunOS/Solaris build problems: added HAVE_SYS_INT_TYPES_H and
-   changed index_t to xtd_seq_num_t (see include/rdbx.h).
-
-   Fixed SEAL3.0 output byte buffering, added byte-buffering test to
-   cipher/cipher-driver.c.
-
-   Fixed roc-driver so that the non-sequential insertion test
-   automatically recovers from bad estimates.  This was required to
-   prevent spurious failures.
-
-   Made rdbx_estimate_index(...) function smarter, so that initial RTP
-   sequence numbers greater than 32,768 don't cause it to estimate the
-   rollover counter of 0xffffffff.
-
-
-1.0.0   Initial release
-