Change API enums to enum class, remove now redundant prefixing

* This gives a little nicer syntax, a bit better type safety, and also
  reflects better for SWIG bindings. Overall it's a minor change but
  better.
* We don't update the C# UI at all, since it's soon to be removed and
  not worth the effort/code churn.
* For now so we're ABI compatible with C#, all enums are uint32_t, but
  that is an obvious optimisation in future to reduce struct packing.
* We avoid 'None' as an enum value, because it's a reserved word in
  python so will cause problems generating bindings.

renderdoccmd/renderdoccmd_win32.cpp

@@ -250,11 +250,8 @@ void DisplayRendererPreview(IReplayRenderer *renderer, TextureDisplay &displayCf
   UpdateWindow(wnd);
 
   IReplayOutput *out =
-      ReplayRenderer_CreateOutput(renderer, eWindowingSystem_Win32, wnd, eOutputType_TexDisplay);
+      ReplayRenderer_CreateOutput(renderer, WindowingSystem::Win32, wnd, ReplayOutputType::Texture);
 
-  OutputConfig c = {eOutputType_TexDisplay};
-
-  ReplayOutput_SetOutputConfig(out, c);
   ReplayOutput_SetTextureDisplay(out, displayCfg);
 
   MSG msg;