Fix brain_test.coffee

We need to pass a Robot (well, a mock Robot) to the Brain constructor.
And we need to wait for the save interval to elapse before testing
whether the brain was saved/closed, so do it in a timeout rather than
whenever the process exits.
Ensure that User#name is always a string

User uses its ID as its name by default. In Campfire, user IDs are
Numbers, so if we aren't careful we can end up with User#name being a
Number too. This can trip up code that is expecting a String.
Merge pull request #791 from aroben/names-must-be-strings

Ensure that User#name is always a string