Implement test scenes in nfRendererDemo

[Witek902]

Tests scenes to be implemented:

• [x] Basic (simple vertex and index buffer, vertex layout, texture, constant buffers)
• [x] DepthStencil (simple 3D scene with depth and stencil buffer usage)
• [x] VertexBuffers (more advances vertex buffers - using multiple vertex buffers in vertex layout, instancing, dynamic vertex buffers)
• [x] RenderTargets
  • [x] subscene 0 - single rendertarget, no depth buffer
  • [x] subscene 1 - single rendertarget, with depth buffer
  • [x] subscene 2 - multiple rendertargets, with depth buffer
• [ ] Multiple shader resources bindings (multiple textures, cbuffers, samplers bound to vertex shader, pixel shader and geometry shader)
• [x] Multithreading (multithreaded resources creation, multithreaded rendering, command lists reuse)
• [x] Compute shaders