History or versions

I was trying to see why I didnt have the versions button in the content editor of one site. 

Finally I discovered in the options that the option is labelled as History not versions. In my opinion this is confusing. If I am looking for the versions feature it should be labelled versions not history.

![id13](https://cloud.githubusercontent.com/assets/1296369/4628664/2ee834e0-539a-11e4-9d71-9dcd6fc340c9.png)

This PR changes the label to say Versions

![kmg7](https://cloud.githubusercontent.com/assets/1296369/4628682/700d6184-539a-11e4-8199-e84d2fc58ebe.png)

As you can see it now says Save Versions and Maximum Versions and not Save History and Maximum Versions which I believe to be confusing