Port "Paired down OS Lua library" from SRB2

This is a port of this MR STJr/SRB2!2060 (merged) from regular SRB2 created by Sal to Kart. This adds the OS library which is primarily used for time based functions since it has been stripped of other stuff. Uses include seeding RNG or getting time and date. Included file is an example script that should run with this on Kart.Timetest.lua