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.
Implemented the game options menu and added all three options in it.

What's left is to make the game actually apply the game difficulty, but that's for another issue.

Fixes #155
Renamed the battle status effect supervisor to a better name.

Another way to fix #380