* Partially rewrite channel password handling, fixing some UI out-of-sync quirks and improving naming consistency.
* Simplify channel auto-join and rejoin code.
* Fix a few bugs around rejoining channels after reconnects related to the cause of the disconnect, channel passwords and picking the actual list of joined channels over the network's auto-join list.
* Improve behavioral consistency in situations where the auto-join list is pre-empted by a transitory auto-join channel (bookmarks, etc.).

Some of this is stop-gap stuff until the connection management rewrite is merged, but the unrelated improvements required it, plus Juan's upcoming auto-join context menu stuff as well.