API: Allow texture modifiers in node registration

If using texture modifiers, you must use the full texture name.

api.lua

@@ -118,6 +118,7 @@ function microexpansion.register_node(itemstring, def)
   -- Update texture
   if auto_complete ~= false then
     for _,i in ipairs(def.tiles) do
+      if #def.tiles[_]:split("^") <= 1 then
         local prefix = ""
         if def.type == "ore" then
           prefix = "ore_"
@@ -126,6 +127,7 @@ function microexpansion.register_node(itemstring, def)
         def.tiles[_] = BASENAME.."_"..prefix..i..".png"
       end
     end
+  end
   -- Colour description
   def.description = desc_colour(def.status, def.description)
   -- Update connect_sides