Fix "rgba" colors in `me.video.clearSurface()`
Fix "rgba" colors in `me.video.clearSurface()`

- Use the proper width/height for the given context.
- Clear the context before filling to fix additive alpha bugs.

TukekeSoft/melonJS,melonjs/melonJS,gopalindians/melonJS,srbala/melonJS,TukekeSoft/melonJS,Smoss/Enoru-eco,srbala/melonJS,MarkoIvanetic/melonJS,melonjs/melonJS,rlugojr/melonJS,MarkoIvanetic/melonJS,gopalindians/melonJS,rlugojr/melonJS,TukekeSoft/melonJS,gopalindians/melonJS,rlugojr/melonJS,Smoss/Enoru-eco,srbala/melonJS