[WIP] Prevent duplicate environment clones

Upon clicking CLONE after selecting an already cloned environment, a warning appears telling the user:

![NO](http://i3.kym-cdn.com/entries/icons/original/000/007/423/untitle.JPG)

The user is however presented with a link through to that environment so they can still see what it looks like.

![YAY](http://sameffect.com/wp-content/uploads/2013/06/happy-meme.png)