Added Tor

ports/tor/README.nacl

+Tor for NaCl
+=================
+This is a port of Tor(core) to NaCl platform.
+For details visit : https://www.torproject.org
+
+**The port is functional albeit with some quirks, this document lists and
+keeps track of all those.**
+
+1. **Currently there is no reliable way of checking if another tor process is 
+   running.**
+
+   **Reason:** NaCl don't support file locking(yet) 
+
+   **Details:** Since Chrome 34, by default multiple windows per Chrome app 
+      is not allowed,this should take care of the problem. 
+      In the code, file locking is commented out altogether,
+      see /src/or/config.c [line 1379]
+
+2. **Maximum file descriptors are hard coded to 15000**
+   
+   **Reason:** getrlimit not implemented
+
+3. **UID mismatch is ignored**
+
+   **Reason:** On NaCl, the UIDs are not preserved(properly)
+  
+   **Details:** To debug/see implementation see /src/common/util.c [line 2195]
+
+4. **Callbacks due to signals are NOT supported.**
+
+   **Reason:** nacl.io don't support POSIX signals.
+
+   **Details:** sigaction(...) and signal(...) are not(yet) implemented on 
+     NaCl.io,thus the calls evsignal_add,evsignal_del,evsignal_pending should 
+     be avoided,also event_add/event_del when passed with EV_SIGNAL will 
+     also fail.
+
+  For details about these functions visit :
+  http://www.wangafu.net/~nickm/libevent-book/Ref4_event.html
+
+  To debug/see implementation (see libevent port)
+  Look for /event.c, /signal.c and /evmap.c
+  In /signal.c see function _evsig_set_handler and _evsig_restore_handler
+
+  Typical function call
+  event_add > event_add_internal > (if signal) evmap_signal_add > evsig_add
+
+5. **Post build tests are skipped.**
+
+  **Reason:** There are some unresolved dependencies when compiled against 
+  glibc + i686. For now they are altogether skipped for every 
+  toolchain + architecture.[they work fine against clang-newlib]
+
+6. **Build against glibc is not functional.**
+  
+   **Reason:** unknown (issue de-prioritized,glibc disabled in pkg_info)
+
+**Notes**
+
+ - Socket api is only allowed in chrome apps, remember to load 
+   published directory as chrome app instead of make run / make serve
+ - The default port is 9999 instead of usual 9150, 
+   thus point your (socks)proxy to 127.0.0.1:9999
+ - Once the GUI is ready, parameters can be generated/modified as per the user