* Set depth of events and whether they need to be federated.

Set the depth of each new event to one greater than the maximum depth
of it's direct ancestors.

Add a flag to each event passing through the roomserver that tells us
whether the event needs to be sent over federation.

We do this by passing the name of the server to send the event as.
We will need this capability if we want to support vhosting as it is
not possible to tell from the event alone which server to send it as.

(The reason for this is that sometimes a event needs to be sent on
behalf of a different remote matrix server)

* Update roomserver integration tests

* More comments

* Constants and comments

* Fix comments

* Document the int64 returned by LatestEventIDs

* Start implementing the join room API

* Hacks to get join room working

* Make the TLS fingerprint configurable

* Fix the client API proxy to handle '#' correctly

* Return a 200 OK response

* Write the join event along with current state to the room server

* Comment on the error handling

* Fix typos

* Fix tab

* Add TODO for moving authEventIDs to gomatrixserverlib

* Comment on why we ignore the key ID argument for local keys

* Avoid 'preceeded'

* Neaten the control flow

* Neaten the control flow even more

* Return pointers

* Rename err to lastErr for the loop