Removed the backbuffer canvas because it literally does nothing but decrease performance.
Revert "Removed the backbuffer canvas because it literally does nothing but decrease performance."

This reverts commit b457cf2f007d92583b3c80ddad356b765cf6a162.
Fix double buffering and made it optional. Default: false
Merge pull request #256 from spilgames/254-backbuffer

254 backbuffer