version 2.3
-----------
 - added ./configure script for better support of Intel C compiler and dependencies [thanks to pdknsk]
 - tweaked quality metric to better estimate quality of images with large solid backgrounds [thanks to Rolf Timmermans]

version 2.2
-----------
 - preserving of unknown PNG chunks (enables optimized Android 9-patch images)
 - improved color profile support: cHRM & gAMA as alternative to ICC profiles, OpenMP acceleration
 - improved support for Intel C Compiler, speedup in 32-bit GCC, and some workarounds for Visual Studio's incomplete C support

version 2.1
-----------
 - option to save files only if they're compressed better than the original
 - option to generate posterized output (for use with 16-bit textures)
 - support for ICC profiles via Little CMS library

version 2.0
-----------
 - refactored codebase into pngquant and standalone libimagequant
 - reduced memory usage by further 30% (and more for very large images)
 - less precise remapping improving speed by 25% in higher speed settings
 - --output option for writing converted file under the given path
 - light dithering with --floyd=0.5
 - fixed regression in dithering of alpha channel

version 1.8
-----------
 - min/max quality option (number of colors is automatically adjusted for desired quality level)
 - switched option parsing to getopt_long (syntax such as -s1 and --ext=ext is supported)
 - significantly improved performance thanks to custom partial sorting
 - optional Cocoa (Mac OS X) image reader for color profile support
 - reduced memory usage by 20%
 - remapping improved for very low number of colors

version 1.7
-----------
 - new, accurate RGBA color similarity algorithm
 - change of optional SSE3 code to SSE2 that is always enabled on x86-64
 - optional OpenMP-based parallelisation of remapping
 - changed long options to use double hyphen (-force to --force) [thanks to Jari Aalto]

version 1.6
-----------
 - novel dithering algorithm that doesn't add noise unless necessary
 - perceptual weighting of colors taking into account edges and noise
 - much faster remapping
 - improved portability, makefiles and man page

version 1.5
-----------
 - palettes postprocessed with Voronoi iteration
 - better RGBA color similarity algorithm and Floyd-Steinberg remapping
 - SSE optimisations

version 1.4
-----------
 - median cut is applied many times in a feedback loop
 - speed/quality trade-off option
 - faster remap of transparent areas

version 1.3
-----------
 - significant changes to the algorithm: use of variance
   to find largest dimensioin and to split most varying boxes
 - use of premultiplied alpha for color blending
 - conversion of output to gamma 2.2

version 1.2
-----------
 - color computation done in floating point
 - gamma correction applied
 - dropped support for very old systems & compilers

version 1.1
-----------
 - alpha-sensitive color reduction and dithering
 - support -- and - arguments in command line
 - number of colors optional (defaults to 256)
 - increased maximum number of colors in histogram

version 1.0
-----------
 - cleaned up Makefile.unx (better gcc optimizations, "clean" target)
 - recompiled binaries with zlib 1.1.4

version 0.95
------------
 - fixed Win32 filter bug (binary mode for stdin/stdout)
 - fixed cosmetic "choosing colors" verbosity buglet
 - fixed palette-size bug when number of colors in image < number requested
 - fixed sample-depth bug (png_set_packing() not retroactively smart)

version 0.91
------------
 - fixed some verbose/non-verbose oopers
 - fixed Win32 (MSVC) portability issues (getpid(), random(), srandom())
 - added Makefile.w32 for MSVC (tested with 5.0)

version 0.90
------------
 - added support for multiple files on command line
 - changed stdin support to write PNG stream to stdout (not "stdin-fs8.png")

version 0.75
------------
 - added support for any type of input file [Glenn Randers-Pehrson]
 - fixed palette-(re)scaling bug
 - added -verbose and -quiet options (default now is -quiet)
 - added palette-remapping to minimize size of tRNS chunk
 - made Floyd-Steinberg dithering default
 - changed output naming scheme to -fs8.png and -or8.png (FS or ordered dither)

version 0.70
------------
 - first public release
