CLOSEWIN

   Synopsis:
      Closes the task window

   Notes:
      If the script is being run from within a task, this statement asks the
         task to close the task window.

   Requires:
      If the script is not being run as a task, or if not task window is open,
         the CLOSEWIN statement is ignored (and no error message is generated).
         Execution continues with the next statement.

   Examples:
      OPENWIN
      WRITEWIN "Hello world!"
      PAUSE 5
      CLOSEWIN
