video: speed up SDL_FillRect[s] slightly (thanks, Jakub!). "This patch does the following: * Instead of SDL_FillRects calling SDL_FillRect in a loop the opposite happens -- SDL_FillRect (a specific case) calls SDL_FillRects (a general case) with a count of 1 * The switch/case block is moved out of the loop -- it modifies the color once and stores the fill routine in a pointer which is then used throughout the loop" Fixes Bugzilla #4674.