Do not allow random() to take an array of high or low, just an optional fixed length...

Do not allow random() to take an array of high or low, just an optional fixed length (otherwise it will randomly select one)

* Functions.php:
(BSFunctions::random): Do not accept an Array as a parameter, just an optional int
* UnitTest/FunctionsTest.php:
(FunctionsTest::testRandom): Test using a fixed length as well as the random length