pngtodo.txt - list of things to do for pnglib

for 1.0 Beta
	finish transformations - namely gamma, background, alpha, dither
   build test suite and testing program
   test, test, test
   memory model support
   better documentation for using and modifying pnglib

for 1.0 or 1.1 (I'd like these to be in 1.0, if they can be finished
      in time).
	optional palette creation
	histogram creation
	text conversion between different code types
   cHRM transformation
   support for other chunks being defined (sCAl, the gIF series,
      and others that people come up with).

for 1.1
	push reader (