Issue #575 : forcer réservation tuto/articles
override_settings sur MiniTutorialTests
Merge pull request #632 from ShigeruM/issue_575_forcer_reservation_tuto_2

Issue #575 : forcer réservation tutos et articles
réduit significativement la vitesse de travis
Merge pull request #642 from zestedesavoir/travis_ameliorations

réduit significativement la vitesse de travis
corrige les problèmes en cas de non connexion
Merge pull request #644 from zestedesavoir/issue_643

corrige les problèmes en cas de non connexion
add htmlcov folder to gitignore
create gallery/tests folder to separate tests files
add forms gallery tests
add models gallery tests, fix get extension for image, delete medium/thumb images
remove del_image function in views, not use in application

not declared in urls, but still dangerous to keep function like this. No verification was made with user permissions.
ajout de tests pour les vues des galeries