Prettier WSGI error page
Made NotFoundError a little bit more accessible
Better "not found" messages

Not logged, proper display
Nicer display of service-generated FormValuesErrors
Style fixes, mostly PEP8
Do not propagate conflicts
Change LHC RBB style to CERN Committee
Make Cern Committee style more readable
Fix css for long contribution titles

* Limit contribution title in CERN Committee style
* Add padding to itemTime
Preselect room when booking for event with a room
Fix accepting prebooking with colliding prebookings
Improve 'Conflicts at the same time'

- Only show header if there are actually conflicts
- Remove ugly spaces inside parentheses
Fix booking search for both cancelled & rejected

Since a booking cannot be have both states at the same time, it makes
sense to search for bookings in either state if both are selected
Fix iterdays wrong days when sTime > eTime