def irc_upcase(irc_string, casemapping = :rfc1459)
      result = irc_string.dup
      irc_upcase!(result, casemapping)
      return result
    end
def irc_upcase(irc_string, casemapping = :rfc1459)
      result = irc_string.dup
      irc_upcase!(result, casemapping)
      return result
    end
Turn a string into IRC upper case.
 @param [String] irc_string An IRC string (nickname, channel, etc)
 @param [Symbol] casemapping An IRC casemapping
 @return [String] An upper case version of the IRC string according to
   the casemapping.