this gives us a great level of control over how we build SDL2, omitting parts we don't want, and including parts we do want, like libusb support!
windows sdl2 normally doesn't support libusb, but with some magic it can be built and linked in fairly easily, giving windows sdl2 libusb support.
libusb support in sdl2 means official GC adapter support! (resolves#1879)
linux build will be done in a later commit
The main objective in this PR is to get rid of the main .NET Framework dependencies in Bizware packages. This PR doesn't do that completely per se, still having .NET Framework used for WinForms Controls, but that can easily be swapped over for whatever UI framework we use next as long as it exposes native window handles in some way.
For this PR, it does some reorganizing of Bizware, splitting Bizware.OpenTK3 and Bizware.DirectX into 3 packages based on usage; Bizware.Audio, Bizware.Graphics, and Bizware.Input. These packages in the future probably could have more functionality moved into them, but for now they are largely just a reshuffling of the Bizware.OpenTK3 and Bizware.DirectX packages.
As both SlimDX and OpenTK3 are .NET Framework, they have been removed in this PR. Their replacements are as follows:
SharpDX: DirectSound, Direct3D9
Vortice: XAudio2, DirectInput/XInput
Silk.NET: OpenAL, OpenGL
SDL2-CS / native SDL2: OpenGL context management, new gamepad backend (replacing OpenTK's role for gamepads)
native X11: New key input backend (replacing one of OpenTK's roles for keyboards)
GLControl has been replaced by custom made control which just uses SDL2 for context management.
The OpenTK input backend has been replaced with a combination of SDL2 and an OS tailored key input backend (DirectInput on Windows, X11 on Linux, and planned to be Quartz on macOS). This is just represented on the user side as "SDL2" without mentioning the key input backend. This does mean for a while DirectX will be mandatory on Windows again, until a RAWINPUT backend is written for handling key input on Windows for the SDL2 input backend.
CasualPokePlayer