Add auto-restrict from Bronco and modify system of refreshing

1) secure administration with auto_restrict script.
2) If refreshing was not done on the same day than the last day of refresh, button never appear. Now, if it's done on the same day, day and hour are printed. If it's not the case, only the date is printed.
Create auto_restrict.php
Create login_form.php
Update admin.php
Update admin.php
Update archive.php
Doctype line 106 deleted
Add auto-restrict
Merge pull request #2 from jerrywham/master

Utilisation du script auto_restrict pour sécuriser l'admin et modification de la vérification de la date du dernier refresh