Remove support for Python =< 2.5, reorder setup.py
Forward-compatibility for repoze.who as in TurboGears/tg2devtools#f6fb49c384
Use the paginate decorator for paginations

Instead of messing around with Page by hand.
Necessary for future-compatibility when TG2 drops webhelpers.
Set max_items_per_page to some big int and let teachers see non-public NewsItems