MINOR: lua: Add proxy as member of proxy object.

MINOR: lua: Add proxy as member of proxy object.

By Adis Nezirovic:

   This is just for convenience and uniformity, Proxy.servers/listeners
   returns a table/hash of objects with names as keys, but for example when
   I want to pass such object to some other Lua function I have to manually
   copy the name (or wrap the object), since the object itself doesn't
   expose name info.

This patch simply adds the proxy name as member of the proxy object.