Port to Python 3.

All scripts and modules have been ported to Python 3 and appear to
work.  Some changes to the lighttpd configuration were needed.

py/cleandb.py

@@ -1,4 +1,4 @@
-#!/usr/bin/python
+#!/usr/bin/python3
 # cleandb.py: empty the database in an orderly fashion
 
 import rlgalldb as rlgall