Repair broken parent link in the scanner
add some comments
remove unused argument
handle http accept headers more gracefully
fix indention
also handle lowercase headers
Update manager.php

add a function getUserGroupIds for retrieving group ids instead of group objects. this significantly improves performance when using many (nested) groups.
drastic speedup for nested ldap groups

Changes a function call in getUserGroups to only retrieve group ids instead of objects.
this change significantly improves performance when using owncloud with many groups, e.g. nested ldap hierarchy (1.2.840.113556.1.4.1941), since getUserGroups gets called in oc_share::getItems, which is needed for every page request.
in my particular case, it took more than 10s to load the calendar page and more than 6s to load the file page.
this was in an environment with 100 user groups (nested) per user. The performance was bad due to the following call stack:
self::getManager()->getUserGroups($user)
  - getGroupObject() (executed for every group!)
     - groupExists() (resulting in many ldap-requests)
since the groups are loaded from ldap, it is unnecessary to check whether the group exists or not.
Reduce size of png files so they match the svg

Fix #8996
Fix header menu background in IE8
Fix missing caret in header menu for IE8
Update group.php
Update manager.php
fix liskov substitution principle in admin mail template settings, fixes #8997
Merge pull request #8980 from owncloud/better-accept-header

handle http accept headers more gracefully
Move IE8 fixes to fixes.css
Merge pull request #8999 from owncloud/issue/8996

Issue/8996 IE8 issues with the new menu
Added check and cleanup for storage/filecache

Some tests don't clean up the file cache and sometimes entries are
reused by mistake in subsequent test suites.

This cleans up the file cache and storage after every test suite and
also shows an annoying warning.
Merge pull request #9003 from owncloud/fix_liskov_in_admin_mail_template_settings

fix liskov substitution principle in admin mail template settings
Merge pull request #8998 from macjohnny/master

drastic speedup for nested ldap groups