Remove import of deleted module
Check booking/prebooking permissions when booking
Some improvements in the new booking RH
Move reservation creation into Reservation class
Use WTForms for book/prebook buttons
configure mappers explicitly

Otherwise backrefs are not created until something is queried
http://git.io/c_t_hA
Use localtime for all room-booking related times

This only affects times that are actually related to bookings/rooms.
E.g. start/end dates. Purely display datetimes such as creation time are
stored in UTC and displayed in the user's timezone.
Fix prebooking conflict bars
Holiday validation uses now date_time utils
Fixed messagebox weird padding
Pre-booking conflict check moved

* Pre-booking conflict warning appears now next to confirmation button
* Refactored overlapping methods in Reservation/ReservationOccurrences
* Added some date_time helpers to TemplateExec
* Removed old template and RH
Add missing .all()

Otherwise the preoccurrences iterator will yield zero items in the
second time it's used
Adapted 'book single room' page

* Refactored BookingConfirm RH
* Splitted common elements in booking pages in several widget templates
* Refactored clientside validation
* Rendered repeatability/flexible days with WTForms
* Fixed holidays warning
* Fixed rendering glitch in RB calendar for single room
* Removed old template
* Added callback to timerange widget
* Minor style tweaks
Post-WIP fixes