! Copyright (c) 1990-1997  Michael Sandrof, Troy Rollo, Matthew Green,
! and other ircII contributors.
!
! All rights reserved.  See the HELP IRCII COPYRIGHT file for more
! information.
!
Usage: BIND <key> TOGGLE_INSERT_MODE
  Toggles the INSERT_MODE variable.  This function is equivalent
  to doing:  
    SET INSERT_MODE TOGGLE
