remove unused imports
wrap SDL_GetVideoInfo; supporting conversions for SDL_PixelFormat and SDL_Palette
wrap SDL_GetTicks
Merge pull request #54 from robn/get-ticks

Wrap SDL_GetTicks
Merge pull request #51 from robn/remove-unused-imports

Remove unused imports
Merge pull request #53 from robn/video-info

Implement video::get_video_info