Updates the PNG library to 1.2.37, enables some functionality for O3D

third_party/libpng/README

-README for libpng version 1.2.36 - May 7, 2009 (shared library 12.0)
+README for libpng version 1.2.37 - June 4, 2009 (shared library 12.0)
 See the note about version numbers near the top of png.h
 
 See INSTALL for instructions on how to install libpng.
 
 Libpng comes in several distribution formats.  Get libpng-*.tar.gz,
 libpng-*.tar.lzma, or libpng-*.tar.bz2 if you want UNIX-style line
 endings in the text files, or lpng*.7z or lpng*.zip if you want DOS-style
 line endings.  You can get UNIX-style line endings from the *.zip file
 by using "unzip -a" but there seems to be no simple way to recover
 UNIX-style line endings from the *.7z file.  The *.tar.lzma file is
@@ skipping 175 matching lines @@
        netware.txt      =>  Contains instructions for downloading a set of
                             project files for building libpng and zlib on
                             Netware.
        wince.txt        =>  Contains instructions for downloading a Microsoft
                             Visual C++ (Windows CD Toolkit) workspace for
                             building libpng and zlib on WindowsCE
       scripts       =>  Directory containing scripts for building libpng:
        descrip.mms      =>  VMS makefile for MMS or MMK
        makefile.std     =>  Generic UNIX makefile (cc, creates static libpng.a)
        makefile.elf     =>  Linux/ELF makefile symbol versioning,
-                            gcc, creates libpng12.so.0.1.2.36)
+                            gcc, creates libpng12.so.0.1.2.37)
        makefile.linux   =>  Linux/ELF makefile
-                            (gcc, creates libpng12.so.0.1.2.36)
+                            (gcc, creates libpng12.so.0.1.2.37)
        makefile.gcmmx   =>  Linux/ELF makefile
-                            (gcc, creates libpng12.so.0.1.2.36,
+                            (gcc, creates libpng12.so.0.1.2.37,
                             uses assembler code tuned for Intel MMX platform)
        makefile.gcc     =>  Generic makefile (gcc, creates static libpng.a)
        makefile.knr     =>  Archaic UNIX Makefile that converts files with
                             ansi2knr (Requires ansi2knr.c from
                             ftp://ftp.cs.wisc.edu/ghost)
        makefile.aix     =>  AIX makefile
        makefile.cygwin  =>  Cygwin/gcc makefile
        makefile.darwin  =>  Darwin makefile
        makefile.dec     =>  DEC Alpha UNIX makefile
        makefile.freebsd =>  FreeBSD makefile
        makefile.hpgcc   =>  HPUX makefile using gcc
        makefile.hpux    =>  HPUX (10.20 and 11.00) makefile
        makefile.hp64    =>  HPUX (10.20 and 11.00) makefile, 64 bit
        makefile.ibmc    =>  IBM C/C++ version 3.x for Win32 and OS/2 (static)
        makefile.intel   =>  Intel C/C++ version 4.0 and later
        libpng.icc       =>  Project file, IBM VisualAge/C++ 4.0 or later
        makefile.netbsd  =>  NetBSD/cc makefile, PNGGCCRD, makes libpng.so.
        makefile.ne12bsd  =>  NetBSD/cc makefile, PNGGCCRD, makes libpng12.so
        makefile.openbsd =>  OpenBSD makefile
        makefile.sgi     =>  Silicon Graphics IRIX (cc, creates static lib)
        makefile.sggcc   =>  Silicon Graphics
-                            (gcc, creates libpng12.so.0.1.2.36)
+                            (gcc, creates libpng12.so.0.1.2.37)
        makefile.sunos   =>  Sun makefile
        makefile.solaris =>  Solaris 2.X makefile
-                            (gcc, creates libpng12.so.0.1.2.36)
+                            (gcc, creates libpng12.so.0.1.2.37)
        makefile.so9     =>  Solaris 9 makefile
-                            (gcc, creates libpng12.so.0.1.2.36)
+                            (gcc, creates libpng12.so.0.1.2.37)
        makefile.32sunu  =>  Sun Ultra 32-bit makefile
        makefile.64sunu  =>  Sun Ultra 64-bit makefile
        makefile.sco     =>  For SCO OSr5  ELF and Unixware 7 with Native cc
        makefile.mips    =>  MIPS makefile
        makefile.acorn   =>  Acorn makefile
        makefile.amiga   =>  Amiga makefile
        smakefile.ppc    =>  AMIGA smakefile for SAS C V6.58/7.00 PPC
                             compiler (Requires SCOPTIONS, copied from
                             scripts/SCOPTIONS.ppc)
        makefile.atari   =>  Atari makefile
@@ skipping 19 matching lines @@
 -Glenn Randers-Pehrson (current maintainer)
  Internet: glennrp at users.sourceforge.net
 
 -Andreas Eric Dilger (former maintainer, 1996-1997)
  Internet: adilger at enel.ucalgary.ca
  Web: http://members.shaw.ca/adilger/
 
 -Guy Eric Schalnat (original author and former maintainer, 1995-1996)
  (formerly of Group 42, Inc)
  Internet: gschal at infinet.com