Added RANROT/B PRNG in Lua

Hi,

RANROT /B pseudo random number geenrator added in Lua.
Note that it was quite tricky to get this to work in Lua.

I havent included real tests (I couldn't think of a straightforward way to test a PRNG, so the
test file only contains an snippet that prints an output of 1000 random values. :)

Regards,
Roland.