v2.0.6

• Security issue: empty password may be accepted by LDAP servers, as they implement the Unauthenticated Authentication Mecanism, allowing empty password. We don't want such feature, so empty password are now refused.
• Fix user group search: escape parenthesis in values inserted into the searchGroupFilter name.
• Fix user group search: add the user in default groups of the application, in addition to groups corresponding to ldap groups. New configuration parameter searchGroupKeepUserInDefaultGroups to disable this feature.