REACH-34: Remove MongoDB dependency.

This PR adds ability to disable data saving in MongoDB, all necessary data are saved in memory. This mode is designed to work with DynamoServer only.
For the base url:  I've created an internal task for it.

For FileSystemStorage:  

One of the expectations of removing MongoDB from the flood client is adding the capability to open dyn files located on the users file system.  In node-webkit mode, flood should be able to request that a dyn file should be opened from the users file system.  Dynamo would actually handle the opening and deserialization of this file.  Upon doing so, it would send a message containing the workspace contents to the client.  

I don't currently see any behavior like that in this system.  If you'd like, we can discuss at greater length over e-mail.

In short, I think the work you've already done should make this straightforward, but I don't quite see it there, yet.  Does that make sense?