split signs_lib from homedecor, put them into their own separate mods

package the two together as a modpack so that regular homedecor users don't
see a functional change, but others can take signs_lib and use it as a
standalone mod.

also get rid of some *~ files

listnodes.sh

@@ -1,13 +0,0 @@
-#!/bin/bash
-
-echo "Node listing as of "`date` > nodes.txt
-
-for i in *.lua; do
-	echo -e "\nIn $i:\n" >> nodes.txt
-	cat $i | grep "minetest.register_node(" | \
-	sed "s/minetest.register_node(.homedecor:/homedecor:/; s/., {//" | \
-	sort  >> nodes.txt
-done
-
-less nodes.txt
-rm -f nodes.txt