stop setting metatables on objects

sim/group.lua

@@ -15,7 +15,7 @@ FFI.cdef[[
 	};
 ]]
 
-function Group.new(self)
+function Group.new()
 	local o = {
 		state = false,
 		fxstate = false,
@@ -32,8 +32,6 @@ function Group.new(self)
 		nout_ports = 0,
 		nin_ports = 0,
 	}
-	setmetatable(o, self)
-	self.__index = self
 	return o
 end