upgrade lua to 5.2
This includes rebuild all the lua modules.
We also need figure out if we want /usr/bin/lua or /usr/bin/lua5.2 or both.
We also need figure out if we want keep a lua5.1 and if so, what do we do with 3rd party modules and 5.1?
(from redmine: issue id 897, created on 2012-01-06, closed on 2013-10-31)