Continue graphics framework

- Replace SFML with GLFW (faulty rendering)
- Update premake4 file accordingly
- Create Shader class to encapsulate OpenGL shaders
- Create Camera class to encapsulate view / projection matrices
- Begin integrating graphics into ECS framework
Shader runtime error - getAttribLocation
Fix buffer / shader bugs - stable

- Add basic Buffer implementations of getBufferEnum / getBufferBindingEnum to fix pure virtual errors
- Decouple shaders from rest of graphics
- Refactor shader get/set
- Basic test working (no way to exit program)
- Improve premake4 file