Fixed duplication mediator bug in issue #71

I didn't want to add any tests as I have no idea how you are all conducting your tests. And if you can create gameobjects etc. I'm using unity test tools. Which all run in editor scripts and work, but it can mess up your scene when you add gameobjects.

Anyways, you can see an example of the bug pre-fix here:
https://www.dropbox.com/s/5g0bqtu169qdz9t/StangeMediationBug.zip