Some XML/ANSI mode changes

Some changes were made to how MUME's output works to make the XML and ANSI
modes behave more similar. This may result in slight changes to how ANSI markup
and XML tags are emitted. Be warned.

Also, two new colour settings ("change colour ...") have been added: "exits"
and "magic" and a few have been renamed (should all be self-explanatory).

- Dáin

PS. Applies as of the next reboot.