Release 0.9.6.0

• Require plugin_dbui 0.9.2 or higher.
• Introduce a new mechanism to deal with author's affiliation.
• Add a new database table affiliation_keys.
• Remove preferences inspirehep_institute_id and add_rules_reg_institute.
• Introduce iterator to scan list of authors and their affiliations.
• Add the script fix_affiliation_keys_0960.py to migrate existing database.
• Update the documentation, add an appendix for HAL Hidden,...