[Engine-VBulletinChatbox] Highlight my own nickname.

A bit weird that this is done completely manually in each protocol.
[Engine-VBulletinChatbox] Improve status messages.

Now output with every relogin or retoken operation, with less copy-paste!
[Engine-VBulletinChatbox] Don't prepend event prefix to commands header.
[Engine-VBulletinChatbox] Remove outdated code.

It unwittingly survived a restructuring...
[Engine-VBulletinChatbox] Fetch security token from FAQ page.

The chatbox archive is a notoriously slow page. The FAQ page seems to be
the most efficient page in terms of processing power, although the data
itself is extracted from the global search form.