Clear session before setup

Fixes https://github.com/owncloud/core/issues/11861
still try to encrypt files, even if the session is not initialized. The stream wrapper will throw an error which is better than silently continue.
throw exception if private key is missing
Remove confusingly names \OC\User\Manager::delete and fix the automatic cache cleanup instead
check if the provided password is really the current log-in password
bower snapjs
Merge pull request #11985 from owncloud/bower-snap

bower snapjs
md5 now handled via bower
Merge pull request #11984 from owncloud/bower-md5

bower md5
Add getLogger() to IServerContainer

Makes my IDE complaining less ;-)
Merge pull request #11993 from owncloud/enc_repeat_password

[encryption] check if the provided password is really the current log-in password
Merge pull request #11972 from owncloud/usermanager-remove-delete

Remove confusingly names \OC\User\Manager::delete and fix the automatic ...
Merge pull request #11883 from owncloud/clear-session-for-setup

Clear session before setup
update to 3rdparty master
Add OCP\Security\IHasher

Public interface for hashing which also works with legacy ownCloud hashes and supports updating the legacy hash via a passed reference.

Follow-up of https://github.com/owncloud/core/pull/10219#issuecomment-61624662
Requires https://github.com/owncloud/3rdparty/pull/136
Merge pull request #11947 from owncloud/public-hash-api

Add OCP\Security\IHasher
Use new hashing API for OC_User_Database

This will use the new Hashing API for OC_User_Database and migrate old passwords upon initial login of the user.
Merge pull request #11998 from owncloud/add-get-logger-to-interface

Add getLogger() to IServerContainer
bower strengthify
Merge pull request #12000 from owncloud/bower-strengthify

bower strengthify