Try to translate simple inline methods literally

[PathogenDavid]

Inline methods in C++ are frequently used for totally trivial methods that could be translated to C# mechanically. For example, ImColor in ImGui:

https://github.com/ocornut/imgui/blob/e5cb04b132cba94f902beb6186cb58b864777012/imgui.h#L1953-L1968

This should be implemented to cover simple cases, and if the method is too complex it just falls back to invoking the method via P/Invoke.