Attempt to fix travis builds
FlxDestroyUtil.destroyArray() now returns null
Merge branch 'dev' of https://github.com/HaxeFlixel/flixel into new_signal
Fix the return type of FlxDestroyUtil.destroyArray() - thanks @kevinresol
Merge branch 'dev' of https://github.com/HaxeFlixel/flixel into new_signal
Make use of the updated FlxDestroyUtil.destroyArray()