Generates a random number.
This function exists in three different versions:
number = random();
With no arguments, the function returns a floating point random number greater than or equal to 0.0, and less than 1.0.
number = random(max);
With one numeric argument, the generated random number will be an integer between 0 and max inclusively.
number = random(min, max);
With two numeric arguments, the generated random number will be an integer between the given min and max inclusively.