fix crash in flow through

flow_through.lua

@@ -3,6 +3,9 @@ local flow_through_directions = {
 	{{x=0,z=1},{x=1,z=0}},
 }
 
+local get_node = minetest.get_node
+local set_node = minetest.set_node
+
 dynamic_liquid.flow_through_abm = function(def)
 
 	minetest.register_abm({
@@ -20,7 +23,7 @@ dynamic_liquid.flow_through_abm = function(def)
 			local source_flowing_node = dynamic_liquid.registered_liquids[source_node.name]
 			local dest_flowing_node
 			if source_flowing_node ~= nil then
-				dest_node = minetest.get_node(dest_pos)
+				dest_node = get_node(dest_pos)
 				if dest_node.name == source_flowing_node or dest_node.name == "air" then
 					set_node(dest_pos, source_node)
 					set_node(source_pos, dest_node)

mapgen_prefill.lua

@@ -1,3 +1,5 @@
+local data = {}
+
 dynamic_liquid.mapgen_prefill = function(def)
 
 	local water_level = def.liquid_level

mineclone.lua

@@ -35,5 +35,8 @@ if dynamic_liquid.config.springs then
 		y_min = -15,
 		pressure = 15,
 	})	
-	
+end
+
+if dynamic_liquid.config.mapgen_prefill then
+	dynamic_liquid.mapgen_prefill({liquid="mcl_core:water_source", liquid_level=water_level})
 end