Preserve active timers at frame move

Previously timers were not copied over to the new nodes when frames
move.  This lead to blinky plants from mesecons to stop working after a
platform has moved, and buttons getting stuck in their pressed state.

Now the timers state for active timers are copied from the old node
positions to the new node positions.

technic/machines/other/frames.lua

@@ -114,7 +114,17 @@ local function move_nodes_vect(poslist,vect,must_not_move,owner)
 	for _, pos in ipairs(poslist) do
 		local node = minetest.get_node(pos)
 		local meta = minetest.get_meta(pos):to_table()
-		nodelist[#(nodelist)+1] = {oldpos = pos, pos = vector.add(pos, vect), node = node, meta = meta}
+		local timer = minetest.get_node_timer(pos)
+		nodelist[#nodelist+1] = {
+			oldpos = pos,
+			pos = vector.add(pos, vect),
+			node = node,
+			meta = meta,
+			timer = {
+				timeout = timer:get_timeout(),
+				elapsed = timer:get_elapsed()
+			}
+		}
 	end
 	local objects = {}
 	for _, pos in ipairs(poslist) do
@@ -133,6 +143,10 @@ local function move_nodes_vect(poslist,vect,must_not_move,owner)
 		minetest.set_node(npos, n.node)
 		local meta = minetest.get_meta(npos)
 		meta:from_table(n.meta)
+		local timer = minetest.get_node_timer(npos)
+		if n.timer.timeout ~= 0 or n.timer.elapsed ~= 0 then
+			timer:set(n.timer.timeout, n.timer.elapsed)
+		end
 		for __,pos in ipairs(poslist) do
 			if npos.x == pos.x and npos.y == pos.y and npos.z == pos.z then
 				table.remove(poslist, __)