Add Visual Studio IDE support

[FiniteReality]

Closes #6

I have no idea if this builds on Linux. Probably not. Either way, I'll use this PR to track Visual Studio support.

C++ Projects

• Loading C++ projects
• Compiling C++ projects
• Running C++ projects

C Projects

• Loading C Projects
• Compiling C Projects
• Running C Projects

General

• Project-to-project references
• Package references
• Full IDE support (intellisense, etc.)
  • Initial IDE support (Visual Studio picks up #included files and shows primitive intellisense, probably because it's smart)
  • Debugging (I have no idea what interfaces I need for this...)
  • Pack support (see Packaging support #2)
  • Getting rid of that weird issue where Visual Studio tries to add a project GUID to the file. I don't know how the .NET SDK/project-system works around this, there's something non-obvious I'm missing.
• 0-100 Installation from VSIX