Frontend: Canvas should be centered, and high scores offset to the side

[johneastman]

Right now, everything formats to the center, but I want the canvas to be at the center of the screen and the high score table to be offset.

[johneastman]

Commit: https://github.com/johneastman/Circles/commit/9acba8fb9848117695ee9fc4552821b5c4854493

Sources that helped:

• https://stackoverflow.com/a/11434041
• http://jsfiddle.net/1Lrph45y/4/