Summoning refinements / QOL easing

- Allow "air equivalent" nodes (e.g. scaling
  and light sources) in the target area.  Players
  can now use torches during summon.
- Summon "sparkles" emit light to help player
  navigate to an exit.

admin.lua

@@ -73,8 +73,7 @@ minetest.register_chatcommand("exmachina_summon", {
 			for x = minpos.x, maxpos.x do
 				for y = minpos.y, maxpos.y do
 					for z = minpos.z, maxpos.z do
-						if minetest.get_node({x = x, y = y, z = z}).name
-						~= "air" then
+						if not (minetest.registered_nodes[minetest.get_node({x = x, y = y, z = z}).name] or {}).air_equivalent then
 							return false, "Area not fully cleared"
 						end
 					end

nodes.lua

@@ -36,6 +36,7 @@ minetest.register_node(modname .. ":field", {
 				backface_culling = false
 		}},
 		paramtype = "light",
+		light_source = 3,
 		sunlight_propagates = true,
 		walkable = false,
 		pointable = false,

schematic.lua

@@ -82,16 +82,18 @@ local function mkcraftnodes(key)
 	return data
 end
 
+local aireq = {air_equivalent = true}
+
 exmachina.craftnodes_summon = mkcraftnodes({
-		_ = "air",
-		c = "air",
+		_ = aireq,
+		c = aireq,
 		x = "nc_tree:eggcorn",
-		f = "air",
+		f = aireq,
 		e = "nc_tree:eggcorn",
 	})
 
 exmachina.craftnodes_banish = mkcraftnodes({
-		_ = "air",
+		_ = aireq,
 		c = "nc_terrain:cobble",
 		x = modname .. ":core",
 		f = modname .. ":frame",