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!