Introducing CardDAV into core

[autoloader] Make sure to load full paths

Add favicon for IE8-10

Add debug log statement for IJobList steps in cron.php

Show the language code in personal settings for unknown languages

Properly throw exception in OC_Mount_Config::getBackendStatus

This reduces a lot of the autoloader magic and makes sure that we
generate full paths in the autoloader.

Mark files_drop as shipped

Fixes https://github.com/owncloud/enterprise/issues/895

Revert OCS error code change from #20135

Make sure that group names are strings not integers

make sure that we update the unencrypted size for the versions

* makes debugging easier

LDAP: attempt to connect to backup server again, if main server is no…

Steps to reproduce:
* having an unknown language set in oc_preferences
* browse the personal settings
* only get listed the first letter of this language in the language chooser

Share2.0 sharemanager

do not bold heading of update screen

OCS -> ShareManager -> DefaultShareProvider

* Added sharemanager class

This is the central class where all API calls talk to (OCS/Activity).
This in turn talks to the share providers to get the actual sharing
done.

It uses all ShareObjects

* Added share class

Simple class to hold all the share properties that is passed around

* Added IShareProvider interface

Interface that providers os a share have to implement.

Adding more tests to the sharing API.

subadmin methods should not return any null user or group

[files_external] fix empty user mounts setting