Suggestion: ignore-others toggle for TownyChat

[MattWillen]

Please explain your feature request to the best of your abilities:

It would be useful to have an option to automatically disable all the existing channels except the one you're talking into.
This allows for more immersion (local chat would really feel local, and trade chat would finally make sense!), and at the same time keeps the chat in a cleaner state.

To make it really complete, an option could be added in the channels list that allows some channels to ignore the above option, so that Staff or admin related chats can be seen by the staff 24/7.
And lastly (hope to not get too heavy on specifics), a permission node or a command that ignores the ignore-others toggle so that if an admin wants to see all the chat channels together (like it is now) he can.