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
Merge branch 'dev' of https://github.com/HaxeFlixel/flixel into dev

Conflicts:
	flixel/text/FlxText.hx
	flixel/util/FlxColor.hx
Merge branch 'dev' of https://github.com/HaxeFlixel/flixel into dev
MouseEventManager: fix for potential crash
FlxTypedButton.destroy(): add a null check
Make all getters and setters private
Update FlxTypedGroup.hx

Stop allocating a new filter function every time we iterate through FlxTypedGroup - FlxTypedGroupIterator already handles null filters.
Small optimization in FlxTypedGroupIterator
FlxMouse: make some variables read-only
Add FlxG.safePut() and IFlxPooled to fix possible crashes in destroy() functions