Finishing the grid drawing changes.
A minor update to the credits.
Changing a list to a vector.
Personal code review of the OpenGL features.  Merged the sprite classes for simplicity.
Fixing a compiler warning.
Fixing a bug with TexSheet::DEBUG_Draw.
Merging some shaders to simplify the code base.
Merge pull request #409 from authenticate/upstream

Updating the debug map mode grids for the OpenGL changes.