Distortion in Firefox

[tjkopena]

Fullscreening in Firefox doesn't respect SHOW_ALL and scales the game to fill the whole screen. This is based on underlying Firefox odd behavior.

See these issues:

• Fullscreen Mode Always Scaling to Fill Screen in Firefox phaserjs/phaser#1256
• fullscreen mode in firefox not working with phaser 2.0.2 phaserjs/phaser#690