delete all children's previews when deleting a folder

add phpdoc
Testcase base class
Do not use uniqid in Group and User tests as it is not unique on windows
Test LargeFileHelperGetFileSize also with ascii only characters

And skip the UTF8 names on Windows as they are not supported
Windows does not support CHMOD, therefor we can not test not writable folders
Add \OC\App\Manager to handle enabling/disabling apps
Do not remove dir entry if it has the same name as the parent

This fixes an issue when a subdir has the same name as its parent, it
would get exluded from the list.
Merge pull request #12162 from owncloud/ext-s3-missingfolderwithsamename

Do not remove dir entry if it has the same name as the parent
Mark skipped until #12085 is merged

See https://github.com/owncloud/core/pull/12175#issuecomment-63054620
Merge pull request #12177 from owncloud/skip-mail-test-for

Mark skipped until #12085 is merged
Fail...
Merge pull request #12181 from owncloud/resubmit-second-fail

Fail...
eliminate OC_Template::printErrorPage in database classes, fixes #12182
Refactor file sharing public link handling

fixes download issue introduced by #10755

Conflicts:
	apps/files_sharing/public.php
Added download size on public sharing
Show warning when invalid user was passed

Sometimes there are bugs that cause setupFS() to be called for
non-existing users. Instead of failing hard and breaking the instance,
this fix simply logs a warning.
errors are already logged
do not output DB information, and do not set header
Merge pull request #11029 from owncloud/fix-share-download

Fix share download
[tx-robot] updated from transifex