#139173 If smileys were not enabled and PHP error messages were set to display, messages would not appear in the chat board.

Made sure both cache timestamp and current time are sent on each update.
Added test intended to prevent join and leave messages from being generated within 5 seconds of the cache timestamp (it doesn't work; see #120629).

Moved settings to admin/settings.
Added default value for automatically archive old messages.

The chat panel would show all on-line users as joining and off-line users as leaving on first update request. This was because users do not update their status unless the cache file timestamp has been updated. I fixed this by suppressing the display of join and leave messages for the first five updates.

Made the user list update more often.

#114717 Removed reference to chatroom.block.js. This file had been removed because it contained unfinished features, and the reference was generating an error message.

Removed the unused chatroom_chat_invites table.

Fixed a bug that prevented messages from being displayed when a chat was opened unless a new message was sent.