Fixed _key[input] having an error

Since input is of Dynamic type, it can't be used directly for the
Map<Int, Bool> key. Added a check and a cast
Merge branch 'dev' of github.com:Anheurystics/HaxePunk into Anheurystics-dev

Conflicts:
	com/haxepunk/utils/Input.hx
Merge branch 'Anheurystics-dev' into dev