SDL2 has an SDLApplication class internally which does the same thing. Fixes this warning:
objc[34880]: Class SDLApplication is implemented in both [...]/QuakeSpasm-SDL2.app/Contents/Frameworks/SDL2.framework/Versions/A/SDL2 (0x10365b5a0) and [...]/QuakeSpasm-SDL2.app/Contents/MacOS/QuakeSpasm-SDL2 (0x1002708e8). One of the two will be used. Which one is undefined.
git-svn-id: svn://svn.code.sf.net/p/quakespasm/code/trunk/quakespasm@1348 af15c1b1-3010-417e-b628-4374ebc0bcbd