setfenv can no longer use the result of proxy.new

[Matthew Dean]

local env = proxy.new({
   environment = getfenv(0)
})
setfenv(0, env)
--> bad argument #2 to 'setfenv' (table expected, got userdata)

[Matthew Dean]

Fixed by making the environment wrapper a table. All other wrappers of tables and userdata are still tables.