Fix crash while updating user account

Due to the switch to django 1.6, we should save the timezone name in the
request context (and not the pytz object).
html pages language based on user profile
Manage datetimepicker local with profile language

Hacked-by: Rémi Duraffort
Outings: ask the ModelFiel to localize the dates
Outings: the date formats are translatable
Update the translation and translate the date format
On the road for v0.5
Upgrade django to 1.6.2
Upgrade bootstrap to v3.1.1
Re-enable striped tables

They were broken by bootstrap some releases ago.
account: lastname should not be required
Add some test for profile updates

This test is able to check that the language and timezone are changed correctly
account: last_name is not required even during update
Test friend request display and selection
Fix friend invitation tests

The invitation view is expecting user primary key and not profile one.
Add GPS position recording

The application can now store GPS point zith time and precision. This is then
used to trace the path if the user is late.
This can be useful to find someone after an accident.
Outing details: add a link to the trace
Add missing file and print the point details
Outing trace: add fullscreen

The leaflet fullscreen plugins can be found at
https://github.com/Leaflet/Leaflet.fullscreen
500: fix an html syntax error