Function:   Decode()

               See Encode() for full details.
               In fact Encode() is a symmetric function, meaning that
               Encoding a string with the same key twice returns the
               original string. a Decode() function, that thus is the
               same as Encode(), has been added however, to make the
               programming clearer.

   Syntax:     Decode(<cCodedStr>,<cKey>) --> cStr

   Arguments:  <cCodedStr> is the string to decode. <cKey> is the keyword
               that was used by encode().

   Returns:    The string, normal again.

   Usage:      if x != Decode(Encode(x,'xxx'),'xxx')
                    MouseAlert("We've got a;SERIOUS;problem here!")
               end