apps/files_external/lib/config.php
apps/files_versions/lib/versions.php
lib/connector/sabre/client.php

Only use a ETag, but include last modified time into this
Also added the filesize to this. And used the ETag for the
internal cache.

Support for unshare from self, with a bunch of temporary fixes to overcome configuration problems with file actions

prefix.

Fixes: oc-1663

Changed oc_preferences configvalue back to clob as it will give us bug reports in calendar, contacts and tasks if less.

Implement support for replacing files during upload with the actions: replace, suggest name, and cancel