Function:    PackTime()

               Just as with PackDate(), PackTime() packs a time
               string in the "HH:MM:SS" format to a 2 char
               string, representing that time. Any odd second
               will be lost (ie. 14:15:11 is stored like
               14:15:10), because we just don't have enough room
               in 16 bits. But it generally good enough.
               See PackDate() for more info.

  Syntax:      PackTime(<cTime>) --> cPackedTime

  Arguments:   <cTime> is the time in "HH:MM:SS" format we wish to
               pack. Note: ':' or '.' or whatever might be used
               to separate hours, minutes and seconds.

  Returns:     That time in packed format (2 bytes), ordered.

  Usage:       * - See PackDate()..