Conflicts:
	stb_image.h

Also disable VC6 automatic precompiled headers which were enabled in some projects.

rename pngsuite/part1 to pngsuite/primary;
check in pngsuite

fix incorrect img_n variable for interlaced files, caused files to be totally incorrect if forcing channel count

fix a few assert()s that weren't STBTT_asserts();
fix missing cast for C++
fix typo in C++ test compilation that prevented it from trying to compile stb_truetype

   STBTT_POINT_SIZE
   documentation for above

stb_rect_pack:
   STBRP_ASSERT

oversample test tweaks