added glAntialias - enabled by default, sets antialias when creating the webgl context
allow passing a promise for gameInit for loading custom assets before startup
rework ui plugin to use mouse down rather then click events
added scrollbar ui object to plugin
fixed bug with zzfx sounds using default randomness if set to 0 randomness
fix some issues with touch gamepad
simplify platformer demo
setup padding in some example tile sheets
Color.setHex can take 3 or 6 length hex colors with optional alpha
added isValid checks to vec2 and color