added thunder sound with Lightning
Merge branch 'master' into thunder
rename Textures to TextureType
texture takes in a TextureType instead of a path
 loading textures into a static map
 added a texture cache to draw shaders
 texture_id_ is really a texture_
Merge branch 'master' into thunder

Conflicts:
	src/sound_engine.cpp
	src/sound_engine.h
circle centered at origin
Merge branch 'master' into deferredLighting
working on deferred frame buffers