Added FlxAcceleromtere and integrated it into FlxG
Updated FlxG variable comment
Added accelerometer initialisation
Added documentation
Fixed imports and package, tweaked documentation
Changed to capital e for the event parameter
Moved FlxAccelerometer initialisation into init()
Added axis documentation, changed sensor to _sensor
Value inversion for iOS and Blackberry
Merge pull request #1016 from KeyMaster-/dev

Added FlxAccelerometer and integrated it into FlxG, closes #887