Set FlxButton scrollFactor to (0, 0) by default
Rename FlxString to FlxStringUtil
Move FlxSave into util package, update template imports
Move FlxSound into system package
Move SpriteSheetRegion into util.loaders
Move FlxPath into util package
Remove template, tools and src dir, as well as build.xml because of the new flixel-tools repo
Merge branch 'dev' of https://github.com/HaxeFlixel/engine into dev