Synopsis:
   t <channel> [<new topic>]
   t [<new topic>]
   
Description:
   With this command you can change the current topic of the specified
   channel.  If no new topic is specified, the current one is displayed.
   If the new topic is not specified AND either the channel name is prefixed
   with a hyphen (a "-") or the hyphen is the only argument, the topic
   for the assumed channel will be removed.

Examples:
   To set a new topic on your channel:
      /t blah Welcome to blah, a very serious channel.
      or
      /t Welcome to blah, a very serious channel.

   To view the current topic for your channel:
      /t blah
      or
      /t
      
   To unset the topic for your channel:
      /t -blah
      or
      /t -
      /untopic

