- the ChatProvider is now a proper singleton rather than providing static
methods for everything (it is accessed through CrowdServer.chatprov)
- it can now be extended to create a custom UserMessage for tells (which can
contain avatar information on systems that want to show an avatar on the
receipt of a tell)
- the ChatProvider API was tidied up a bit as some methods had been addded over
time that were not sufficiently general purpose so their callers will be
changed to use the general purpose APIs.
git-svn-id: svn+ssh://src.earth.threerings.net/narya/trunk@4251 542714f4-19e9-0310-aa3c-eee0fc999fb1