Added SDL_GetTicks() and other functions in SDL_timer.h
Added SDL_GetTicks() and other functions in SDL_timer.h

Signed-off-by: Jacky Boen <fa300ea54aaa01f8ef2702b435003886aca00208@localhost.localdomain>

Abextm/go-sdl2,phicode/go-sdl2,rakyll/go-sdl2,rakyll/go-sdl2,jangler/go-sdl2,krux02/go-sdl2,veandco/go-sdl2,jangler/go-sdl2,Abextm/go-sdl2,jangler/go-sdl2,krux02/go-sdl2,hybridgroup/go-sdl2,phicode/go-sdl2,krux02/go-sdl2,rakyll/go-sdl2,veandco/go-sdl2,gcatlin/go-sdl2,gcatlin/go-sdl2,phicode/go-sdl2,gcatlin/go-sdl2,Abextm/go-sdl2,rakyll/go-sdl2