Fixes a bug where sockets would be rejected if they connected directly
with the 'websocket' transport instead of doing an AJAX connection with
websocket upgrade (e.g. if `transports: ['websocket']` is passed to the
socket.io-client constructor).
See https://github.com/socketio/socket.io/blob/master/docs/API.md#sockethandshake
User.prototype.refreshAccount was responsible for multiple race
condition bugs as well as inefficient duplication of DB queries in an
attempt to correct such race conditions.
It has now been replaced by a more reasonable model:
* Global user account information and aliases are fetched in parallel
on socket connection
* Channel rank is fetched when the user tries to join a channel
The previous commits do not handle all of the edge cases of #583
appropriately. This is a short term solution that will work, but is not
as efficient as it could be. The whole refreshAccount function needs to
be reconsidered and replaced with a more sane way of handling atomic
updates to the user's account state.
