A first approach at fixing s9y for php 7, which makes it possible to
write an entry without any error message. The specific changes are: 1.
__construct for the plugin classes 2. Update Cache Lite to a modern
version to fix its similar constructor problem 3. Remove the
session_regenerate_id call from the session destructor (should get
re-added to session creation where necessary) 4. Remove error handler to
prevent silenced warnings from becoming fatal exceptions
