SDLApp: Fix minimizing full-screen app lose of focus on OSX
SDLApp: Fix minimizing full-screen app lose of focus on OSX

This annoying "feature" happens when our full-screen window loses focus
to another app on multi-display systems. (No idea what side effects this
may have on other platforms yet!)

i8degrees/nomlib,i8degrees/nomlib,i8degrees/nomlib,i8degrees/nomlib