Replace mesecon:<some_function> with mesecon.<some_function> for greater

flexibility and because it was never inteded to be OOP in the first
place.

mesecon.receptor_on and mesecon.receptor_off are provided by wrappers
(mesecon:receptor_on/off) for compatibility, but will be removed. Mod
programmers that use mesecons: Please update!

Also, fix microcontroller polluting the global namespace and remove some
deprecated stuff.

mesecons_extrawires/tjunction.lua

@@ -16,7 +16,7 @@ local tjunction_get_rules = function (node)
 	 {x = 0,  y = 0,  z = -1}}
 
 	for i = 0, node.param2 do
-		rules = mesecon:rotate_rules_left(rules)
+		rules = mesecon.rotate_rules_left(rules)
 	end
 
 	return rules