'validate' dependency

pythonrewrite/bin/CryptoBoxSettings.py

@@ -1,5 +1,8 @@
 import logging
-import validate
+try:
+	import validate
+except:
+	raise CryptoBoxExceptions.CBEnvironmentError("couldn't import 'validate'! Try 'apt-get install python-formencode'.")
 import os
 import CryptoBoxExceptions
 try: