Added a Lua examples page covering most of the current Lua documentation

I haven't rigorously reviewed this, although I did try all the sample code/commands out.  I noticed a request on the mailing list (belatedly) for Lua examples, so I thought this might help.

This only covers (some) of the currently documented functions.  I noticed some additions and changes to the Lua parser since I last looked at it -- I haven't had the chance to read up on them yet, but if it would be helpful I can set aside some time.