/* $DOC$
   $NAME$
      ft_Sleep()
   $CATEGORY$
      Menus/Prompts
   $ONELINER$
      Wait for a specified amount of time
   $SYNTAX$
      ft_Sleep( <nSeconds>, [<nInitial>] ) -> nil
   $ARGUMENTS$
      <nSeconds> is the number of seconds to pause

      <nInitial> is an optional clock value (from a call to Seconds())
                 from which the <nSeconds> seconds are to elapse. Useful
                 for setting a minimum time between the start of events
                 which could take a variable amount of time due to the
                 execution of intervening code.
   $RETURNS$
      NIL
   $DESCRIPTION$
      This routine will wait a specified period of time. It provides
      resolution based upon the execution of the Seconds() function.
      It does not use an input state such as Inkey(). The specified time
      is the minimum time sleeping and will usually be slightly longer.

      The second optional argument allows one to begin timing an event
      prior to executing some operation. This is useful when, for example,
      you input a key or mouse click and wish to do something but still want
      to note if the user double entered (mouse or key) within a certain time
      which in turn may have meaning within your program's context.

      The routine correctly handles passing through midnight but will not
      work for more than 24 hours.
   $EXAMPLES$
      // Example 1:
      ft_Sleep( 10.0 )     // Sleep for 10.0 seconds
      // Example 2:
      nTime := Seconds()   // usually after some interupt from mouse or
                           // keyboard

      // ... intervening code ...

      // ft_Sleep( 0.5, nTime ) // Sleep until the sytem clock is
                                // nTime+0.5 seconds.
   $END$
 */