add options to disable the check for a working .htaccess file in data and for a working WebDAV server. This are advanced settings that are needed in special situations where our check fail and the user runs into an http timeout.

refs #4883

 * http/response.php
 * config.php
 * response.php
 * files.php
 * idbconnection.php
 * app.php
 * user.php
 * template.php
 * share.php
 * db.php
 * icache.php & il10n.php

Fixes #5357

Since SabreDAV does not support passing a timeout value to curl, this
commit adds a subclass for it that will set the timeout value to
curlRequest().

Fixed permissions returned for mount points to not include update and
delete permissions.

Fixes #5291

<a id="logout" href=/projects/owncloud/core/index.php?logout=true>

Callers of streamCopy() expect an array to be returned containing count and result.

blacklist implementation remove because no longer needed

otherwise the returned internalPath will not match followup calls to e.g. Cache::getID()

due to internal implementations touch will always be successful - $mtime will be stored in the cache
from desktop client perspective it is necessary to set the mtime under every condition