Make initial cleanse optional

This in combination with Fotorama was causing bugs for me in Chrome for some reason. I still can't figure out why removing transition & transform by cleansing them even  60 seconds before initializing Fotorama caused bugs, but it did. This is probably the weirdest bug that I've ever encountered. 

In any case - an optional initial cleanse doesn't hurt. Maybe someone has set up their initial transforms & transitions for some reason, or encounters a weird chrome bug like I did.