Sets a channel flag, either on the current channel or on a user on the
channel. Flags may be unset by prefixing them with a !. The current
valid channel flags may be seen with 'help channel-flags'. You must be
a channel pope to set flags on that channel.


@flagchannel foo = private topiclock (makes channel foo private and topiclock)
@flagchannel foo = !moderated (makes channel foo unmoderated)
@flagchannel foo = inky Sargent : pope (makes inky and Sargent channel
                   popes on foo)