Related changes:
- fixes crashes on threads and functions objects creation [#153]
- serializes and deserializes table's metatable [#141]
- now effil will call __index
only if key is not presented in main table [#140]
- effil now supports __index = {}
to search key in another table [#138]
- add effil.next
function. It behaves just like lua next
function. [#135]