Docs improvements, after first Geotrek training
Set path valid default to false (fixes #1217)
Mention database users
Start flatpages application
Flatpages tests
Support external URL field
REST views
List of images in REST API
Update translations, changelog and fixtures
Pep8
More consistent env_* Makefile target

Now env_* targets just run buildout. So you have to explicitely call update
target after env_dev one. Moreover all_compilemessages is added to update
target so it is run by salt install.
Merge branch '1217_default_path_valid' into develop
Add information desk type (ref #1192)
Move information desk to tourism (ref #1192)
Remove retro-compatibility for single information-desk
Add GeoJSON for all information desks (ref #1192)
Update REST API to add type (ref #1192)
Show pictogram in trek detail page (ref #1192)
Merge pull request #1254 from makinacorpus/consistent_makefile_targets

More consistent env_* Makefile target
@Gutard review