Fixed git clone in .travis.yml.
Generalized shader loading
Merged Texture class into material module, merged Shader and GLShader, merged Shader into shaders module, cleaned up imports.
Merge lights into single module. Closes #47.
Merge branch 'cleanup/MergeModules' of https://github.com/Circular-Studios/Dash into feature/EmbeddedShaders
Deferred shaders are now embedded in the engine rather than modifyable by the game programmers.
Also, fixed an order of operations bug in the lighting shader.  Turns out it *wasn't* supposed to look gray!
Changed embedded shaders to be immutable.
Merge branch 'develop' into feature/AnimationSystem
Merge branch 'feature/EmbeddedShaders' into feature/AnimationSystem