XPrandom()
 Return a random number
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   Function:   XPrandom()

               this function returns a Random number, when
               XPrandomize() has not been called, the seed
               used was 100*seconds(), otherwise the seed
               given to XPrandomize() is used, and the Random
               numbers generated are the same, this is called a
               pseudo Random generator, and can be useful for test
               purposes, where one wants the same behaviour for the
               testing of some routines.

               Note that making Truly Random generators (pseudo or not)
               is not trivial. This function is provided "as is", and I
               can't guarantee the "Randomness" of the output. Tests have
               been good enough for me, but might not be good enough for
               some applications.

   Syntax:     XPrandom([nBound]) --> nRandom

   Arguments:  nBound specifies an optionnal bound for the random
               numbers to generate. When omitted, the number returned
               is 0 <= x < 1, otherwise, the number returned is an
               integer between 0 <= x < nBound.

   Returns:    

   Usage:      XPrandom(100)
               * - Returns an integer number between 0 and 99.
               XPrandom()
               * - Returns a number between 0 and 1 (exclusive).