Remove lowercase restriction on mongo database names

Not sure if you guys will be ok with this change or not.

I've had to make it because modulus.io seems to always generate database names that contain an upper case character (at least all of the 10 or so that I created last night contained one). So without this, I can't deploy the new hapi app that I'm working on to modulus.io.

Fwiw, the documentation for mongo doesn't mention anything about upper case characters in its restrictions on database names:

http://docs.mongodb.org/manual/reference/limits/#Restrictions%20on%20Database%20Names