Perform a bit-wise XOR operation.
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 Syntax

        GT_XOr(<nNumber1>,<nNumber2>) --> nResult

 Arguments:

      <nNumber1> and <nNumber2> are two numbers that you whish to
      XOR together.

 Returns:

      The result of <nNumeric1> XOR <nNumeric2>.

 Description:

      GT_XOr() can be used for any bit oriented masking operation. GT_XOr()
      is the functional equivlant of the XOR instruction in assembler and
      the ^ operator in C.

 Examples:

      ? GT_XOr(131,15)           // Print the value of 131 ^ 15.

 Source: XOR.C

 Author:  Dave Pearson