Move FlxSignal macro into separate class for cleaner importing
Make FlxDestroyUtil array functions not terriblemore efficient and less redundant
Merge branch 'dev' of https://github.com/HaxeFlixel/flixel into dev

Conflicts:
	flixel/util/FlxDestroyUtil.hx
Empty the arrays a more efficient way, plus some formatting
Merge pull request #1192 from JoeCreates/dev2

FlxDestroyUtil array and FlxSignal macro improvements