mod_rest: Reject password that fails saslprep earlier (thanks tgy)
Prevents an error later if/when passing the password through saslprep a
second time in the authentication module, since the prep functions now
reject nil
The error reporting could be improved but that would involve adding a
way to pass errors back out of the check_credentials() function.
This module allows sending a message to another MUC room.
@other-room: hello
The message will appear in the other room as as
<first-room/You> hello