improve near_nodes support

plantlife_lib/util.lua

@@ -0,0 +1,14 @@
+-- Biome lib util functions
+
+function pl.get_nodedef_field(nodename, fieldname)
+	if not minetest.registered_nodes[nodename] then
+		return nil
+	end
+	return minetest.registered_nodes[nodename][fieldname]
+end
+
+if minetest.get_modpath("unified_inventory") or not minetest.settings:get_bool("creative_mode") then
+	pl.expect_infinite_stacks = false
+else
+	pl.expect_infinite_stacks = true
+end