batcher commenting
shader commenting
fixed batcher bug (>16 textures crash)

texture, shader program commenting
added .vcxproj union merge to .gitattributes

This should help reduce unresolved merge conflicts, but may cause
deleted files/filters to stick around in the project when there is a
conflict.
removed license comment from files
Merge branch 'ben' into engine_work.  Couple of conflicts on comments,
kept the most complete comments.

Conflicts:
	include/pbj/gfx/batcher.h
	include/pbj/scene/entity.h
	src/pbj/gfx/shader_program.cpp