Clock()

         Un/Installs a resident clock

    Syntax:

         Clock( [lActive], [nPosY], [nPosX], [cColor] ) -> lIsActive

         lActive : A logic value indicating if we want to activate (.T.) or
                   desactivate (.F.) the watch.
                   If parameter is Nil, Clock() returns the actual mode.
         nPosY   : Row position. By default 0.
         nPosX   : Column position. By default 70.
         cColor  : Clock color. By default "N/W"

    Description:

         Shows a watch without the programmer action.

         ATENCION!!
         The watch must be deactivated before exiting to DOS.

    Return:

         The actual watch mode. .T. active and .F. inactive.

    Example:

         Clock( .T., 0, 1, "GR+/B" )
         Inkey(0)
         Clock( .F. )