tablex: Add read only table support.
Tablex: have readonly error function report on level 2 of the call hierarchy.
Tablex: Readonly: Add lua 5.2 meta methods to allow pairs, ipairs and len to work with read only tables. 5.1 will just ignore these meta methods.
Add function to check if an object is empty.
Merge remote-tracking branch 'upstream/master' into empty
Merge pull request #61 from user-none/isempty

Thanks, John!