Update to 8.1.0

Changelog:
Version 8.1.0 July 6th 2015

    Much polishing, stability and performance improvements
    Encryption 2.0
    Updated Documents
    New Mount Options for External Storage
    Federated Cloud ID
    Integrated documentation
    LDAP Wizard Improvements
    Security Improvements
    App store improvements
    Release channels
    ownCloud API work: 190 new calls, 50 replaced
    Many small improvements

(ryoon)