IsBit()

         Determinates if a bit is to 1 or to 0

    Syntax:

         IsBit ( cByte, nBitPos ) -> lIsOn

         cByte   : The byte to treat.
         nBitPos : The bit position inside the byte.

    Description:

         Returns a logic indicating if the selected byte inside the byte
         is to 1 or to 0

    Return:

         A logic indicating answer or Nil if cByte is not a character
         or if nBitPos is not numeric.

    Example:

         lEstaA_1 := IsBit ( "C", 2 )