Log Message:
Update to 4.5.7

Changelog:
Version 4.5.7 Feb 20th 2013

    Fix for 3rd party apps dropping the database
    Fix SubAdmins management
    Fix PHP warnings
    Fix compatibility with some CIFS shares
    More robust apps management
    Remove not needed AWS tests
    Improved mime type parsing
    Several sharing fixes
    Offer the option to change the password only supported by the backend
    More robust auto language detection
    Revoke DB rights on install only if the db is newly created
    Fix rendering of database connection error page
    LDAP: update quota more often
    Multiple XSS vulnerabilities (oC-SA-2013-003)
    Multiple CSRF vulnerabilities (oC-SA-2013-004)
    PHP settings disclosure (oC-SA-2013-005)
    Multiple code executions (oC-SA-2013-006)
    Privilege escalation in the calendar application (oC-SA-2013-007)