Fix some warnings
addded few comments
Fix copy/paste bug in y4m2png help.

This outputs PNGs, not Y4Ms.
First commit of logging code
Cleanup trailing whitespace

Conflicts:
	unix/Makefile
dummy test using Check
mingw32 fix (by brooss)
fix merge conflicts
Include <math.h> for M_PI.

We also need to define _USE_MATH_DEFINES on MSVC for the constants
to be visible.
Add autotools build system
Add gitignore file