fix #2711 using a custom event, also use css selectors over filterAttr

remove jPlayer css rules from core css file

Fixing 4444 master

Cache OC_Util::checkServer() result in session

The return value almost never changes but this function
is called for every request.

Fixing owncloud/core#4301

provide correct path for require_once

* owncloud/fix_4326:
  use __DIR__ instead of realpath
  provide correct path for require_once

use theme name and title for password reset

allow empty configvalue in appconfig

Use plural translations

Send mime-type for new files

Fix sharing defaults

Fix recursive scanner to reusing etags

Do not pass numeric strings to strtotime() when formatting dates.

strtotime() will return false and the date will be formatted as the 0-timestamp
(e.g. January 1, 1970 00:00) otherwise.

show 'More apps' link to app administration directly in app navigation