1. fix the 'Clean load' tests which had been broken by
https://github.com/matrix-org/matrix-react-sdk/pull/399: make sure we clear
localStorage between tests.
2. Test the session rehydration properly by setting the localStorage rather
than setting up the MatrixClientPeg before loading the app.
3. Add some tests for the auto-guest-registration flows.
* Make sure we only get one js-sdk (and update runtime config to match)
* Don't verifyNoOutstandingRequests (since it is hard to be certain which we
will get, and makes the tests too dependent on implementation-specifics).
* Disable color for npm test, to avoid confusing Jenkins
