Implement SDL_SetVideoMode(0,0, ...) to create the canvas in whatever size the <canvas> was in, and not try to resize the canvas to 0x0 pixels. Derive a new test for that from sdl_ogl.c. Fixes #1059.
Merge pull request #1726 from juj/sdl_setvideomode_0_0

SDL_SetVideoMode(0,0, ...)