Media Server is deployed!

Finished the XEP-0070 implementation, the Media Server was ready to be deployed, and yesterday the first tests with Denis' HTTP API + Media Server were excellent! Some bugs, of course, but already fixed, and we are very excited with the result of our efforts.

Although, there are some improvements needed by the Media Server for the next couple of weeks:
- Handle video media previews;
- Handle clients with bare JIDs: the XEP-0070 negotiation with those clients needs to be done via XMPP messages;
- Handle audio media: set length property;
- Documentation.