v0.9.2-alpha patch release

There's some interesting bugs in v0.9.1 like +m and +R on channels not working, and we've done some changes that haven't been fully tested yet like changing how rehashing and XLINEs work under the hood. I'm not yet comfortable cutting a new full release with all these changes so here's an alpha containing them!

Changed

• D-LINE and K-LINE code is now cleaner under the hood and less likely to crash.
• Rehashing is now safer.

Removed

• Removed the draft/message-ids cap since... it doesn't actually exist. The feature is now enabled by default when clients request the draft/message-tags-0.2 capability, as written in the Message IDs spec.
• Removed websocket support (conflicted with existing larger IRCd's implementations and not used by any real clients).

Fixed

• AWAY was sending an incorrect mode string, and now sends the correct mode string.
• The Moderated (+m) and RegisteredOnly (+R) channel modes could not be set. Now they can be set.