Minor comment/style fixes
Comment fix
FlxSprite.replaceColor(): add performance warning, no need to cast
FlxSpriteUtil: tween alpha instead of color in fadeOut() and fadeIn()
Removed double parentheses
Comment change
Merge pull request #1069 from JoeCreates/dev2

Minor comment/style fixes
FlxTypedSpriteGroup: change update order to save FlxObject.last
Merge branch 'dev' of https://github.com/HaxeFlixel/flixel into dev
FlxMath.inBounds() now accepts nulls and comment fixes
Merge pull request #1071 from shinji-yoshida/sprite-group-collision

FlxTypedSpriteGroup: change update order to save FlxObject.last
Merge branch 'dev' of https://github.com/JoeCreates/flixel into dev
Change names of camera scroll bounding methods
Merge branch 'dev' of https://github.com/HaxeFlixel/flixel into dev