Ifdef cleanup and API method split.
Copy Shader.cs to API-specific files.
Remove API-specific things from partials.
Ifdef cleanup and API method split.
Copied ConstantBuffer.cs to API-specific files.
Cull by API
OpenGL build fix.
Ifdef cleanup and API method extraction
Copy SamplerStateCollection.cs to API-specific files.
Cull API specific methods.
Ifdef cleanup and API method split
Copied BlendState.cs to API-specific files
Cull API-specific methods
Ifdef and API method extraction
Copied DepthStencilState.cs to API-specific files
Cull API-specific methods
Added missing copyright headers.
Cleanup and API method extraction
Copy RasterizerState.cs to API-specific files
Cull API-specifics