Switch to new download format and update package scripts

post_update.sh

@@ -0,0 +1,10 @@
+#!/bin/sh
+
+SHELLS="/bin/zsh /usr/bin/zsh"
+
+for _shell in $SHELLS; do
+  if ! grep -q "^${_shell}\$" /etc/shells; then
+    echo "Adding '$_shell' to /etc/shells..."
+    echo "$_shell" | tee -a /etc/shells 1>/dev/null
+  fi
+done