Media plugin option for hiding general tab

I had a case that I had to hide the General tab. The simplest way of doing that was to add one more option in media plugin. Disabling the Tab completely is not fusible, so I had to hide it.

![screen shot 2014-10-03 at 11 27 55](https://cloud.githubusercontent.com/assets/1997886/4504599/6eb42e4a-4ae8-11e4-978f-7ce12c1bfe41.png)

Please tell me your opinion on this solution and if you are happy with adding such an option, merge it. 

Cheers,
Alexandros