@:optionalalign:Null<FlxTextAlign>
charset:String
graphic:FlxBitmapFontGraphicAsset
letter_size:FlxPoint
@:optionalletter_spacing:Null<Int>
@:optionalline_spacing:Null<Int>
@:optionalposition:Null<FlxPoint>
@:optionalscroll_factor:Null<FlxPoint>
@:optionalwidth:Null<Int>