add support for warpMouse in SurfaceSdl20
add support for SDL2 events
SDL: fix SDL2 window title

The title can be set when the window is created,
so we save the set title with setWindowCaption
and use that as a parameter for the SDL_CreateWindow()
function.
remove unecessary diff against mainline
remove a redundant USE_SDL20 in surfacesdl
improve warpMouse in surfacesdl20
use _graphicManagers warpMouse in sdl-events