FlxTypedButton: change status to a property that updates alpha rather than manually set alpha every frame.
Merge branch 'dev' of https://github.com/HaxeFlixel/flixel into dev
Merge branch 'dev' of https://github.com/HaxeFlixel/flixel into dev

Conflicts:
	flixel/ui/FlxTypedButton.hx
Merge branch 'dev' of https://github.com/HaxeFlixel/flixel into dev
Put in some null checks that fix crash bugs in flixel-ui when popups close (closing a FlxSubState in response to a button click can lead to situations where an object is destructed halfway through its update function, leading to null reference errors)
Merge branch 'dev' of https://github.com/HaxeFlixel/flixel into dev
Merge branch 'dev' of https://github.com/HaxeFlixel/flixel into dev

Conflicts:
	flixel/FlxG.hx
	flixel/ui/FlxTypedButton.hx
Merge branch 'dev' of https://github.com/HaxeFlixel/flixel into dev
Merge branch 'dev' of https://github.com/HaxeFlixel/flixel into dev
Merge branch 'dev' of https://github.com/HaxeFlixel/flixel into dev
Added Magenta to FlxColor and put in null check + IFlxDestroyable to FlxText
Add FlxTypedSpriteGroup
Merge branch 'dev' of https://github.com/HaxeFlixel/flixel into dev

Conflicts:
	flixel/text/FlxText.hx
	flixel/util/FlxColor.hx
Add flash gamepad support
Don't invert the xbox y axis in Chrome
Adding FlxTween,tween - which automatically determines whether it needs to create a VarTween or MultiVarTween based on Values parameter.
Exposing complete callback in FlxTimer.
Update CHANGELOG.md
FlxObject: update outdated descriptions
Some more description updates for FlxObject