Add support for Direct3D 12 rendering

[hnkb]

• [x] Context class and device initialisation
• [ ] Handle draw events
• [ ] Handle resize events
• [x] Make sure frame rate is synced to refresh rate
• [ ] Renderer abstract class
• [ ] Hello world renderer
• [ ] Fix problem with D3D 12 context not releasing swap chain correctly (see Defer Issues with Flip)
• [ ] Add Direct2D and DirectWrite support

[hnkb]

The way is to use Direct3D 12 Interop, to create D3D11 and D2D objects side-by-side. There is documentation here.

On constructor you do:

• Create D3D12 device
• Create D3D11On12 device
• Retrieve swap chain back buffers and create D3D11 wrapped resources for each
• Initialise D2D

On each frame:

• Render using D3D12 command list and execute
• Acquire the current back buffer’s wrapped resource
• Issue D2D commands
• Release the wrapped resource
• Flush D3D11 immediate context
• Present