Work around SDL display hotplugging timing issue. (#470)

When adapters suddenly disappear, windows are moved and index of display might have changed, but display events may come after the move event, leading to out-of-bounds exceptions.

src/FNAPlatform/SDL2_FNAPlatform.cs

@@ -1126,6 +1126,12 @@ ref bool textInputSuppress
  int newIndex = SDL.SDL_GetWindowDisplayIndex(
  game.Window.Handle
  );
+
+ if (newIndex >= GraphicsAdapter.Adapters.Count)
+ {
+ GraphicsAdapter.AdaptersChanged(); // quickfix for this event coming in before the display reattach event. (must be fixed in sdl)
+ }
+
  if (GraphicsAdapter.Adapters[newIndex] != currentAdapter)
  {
  currentAdapter = GraphicsAdapter.Adapters[newIndex];