Packaging improvements

- compress images with xz by default (and decompress on install)
- add help menu and command line argument parsing to package.sh
- display packaging status if `pv` command available

install.sh

@@ -41,6 +41,10 @@ for f in $(find $LOCATION/images -name "*.img" 2>/dev/null);do
   echo "importing docker image: $f"
   docker load -i $f
 done
+for f in $(find $LOCATION/images -name "*.img.xz" 2>/dev/null);do
+  echo "importing docker image: $f"
+  xz -d -c $f | docker load
+done
 
 # install systemd service unless running in a docker environment
 if [ ! -f /.dockerenv ]; then