Update mailmap for myself

Dont break the files_external migrator if no user is logged in

[Avatars] Calculate 'sane' hue precissions

We used to get the numeric value of the entrire md5 string which is a
128bit integer. We would then devide this by the maxval of a 128bit int.

There is no need for such huge computations. As we just require a value
between 0 and 255. Thus using two 16 bit values is more than enough to
get the precision we need. By just taking the MSB we get nearly
identical results.

Fix unit tests

Fixes https://github.com/owncloud/core/issues/21345

add target="_blank" to href in setupcheck

Make a modifiable copy of the webdav properties in JS file list

Plugins can extend _getWebdavProperties to add custom properties.
These should not be added to the original properties list, so now the
FileList makes a copy of the array.

Adding integration tests for CalDAV

Add error logging to federation handshake

Restore DB connection after failure

In case of failure, PHPUnit seems to skip `tearDown`, so any useful
assertion messages cannot be shown because `tearDownAfterClass` is
throwing an error because of database usage.

This commit makes sure we also restore the database in
`tearDownAfterClass` to prevent the data root restoration to fail

Restructure travis tests

Fix carddav sharing plugin + adding unit tests

Do not delete background jobs, in case an exception occured

Use new APCu API

Update README.md

[3rdparty] Bump symfony/process to 2.8.0

This one is available since APCu 4.0, since we require APCu 4.0.6 this works fine. Also it brings us PHP 7 compatibility and thus fixes https://github.com/owncloud/core/issues/21095

-Added Facebook into "Get in touch"-section
-Improved Emojis on "Get in touch"-section
-Added Support Information

Allow background jobs to be service names for DI

Use OCP\Util::getVersion instead of the internal private implementation