Moved Core Theme Logos to CSS

In order to make it easier for a user/developer to replace logos in the core theme, I removed the hardcoded `logo.svg` and `logo-wide.svg` from the html, and replaced them with `div`s that use css background-image instead.

This has multiple advantages:
1. The user can now use any filename they want for the logo.  They are no longer forced to use logo.svg or logo-wide.svg.
2. The user can now easily use a JPG, PNG or GIF logo instead of SVG (SVG's are awesome, but used by an unfortunately small percentage of web developers at the current time.  Most probably don't even know how to make an SVG…).
3. The user doesn't have to resort to hacking the core theme template files in order to use a different filename or file type.
4. Greatly simplifies documentation instructions for how to change the logos (http://owncloud.org/theming/).

Signed-off-by: Jake Wilson <jakew@huebnerpetersen.com>
Concatenate string in SQL instead of PHP
use doctrine to construct concat expression
cleanup and actually execute the query
Security Update: session fixation

Previous version is vulnerable to session fixation attack in some situations, guessing non-apache-module-php5 environment. Regeneration of session id should be done here.
Update user.php to fix duplicate session-duplicate
remove fix for IE9 nav bar width
Add missing slash in URLGenerator::getAbsoluteURL(). Refs. #6840
Allow passing a root folder to get the used space from in the quota wrapper
Fix phpdoc
Actually rename the variable
mount: make location of mount.json configurable

do not share users data with config files

Signed-off-by: Tigran Mkrtchyan <tigran.mkrtchyan@desy.de>
Removed '/'. Fixes #7035.

Not sure if that '/' is necessary but it broke things on my installation.
Add unit test for quote wrapper size root
Don't create new thumbnails on the write hook
Test if $url is already prefixed by '/'
Merge branch 'master' into quota-space-root
Merge branch 'master' into quota-space-root
Do not send file list for select all on Download/delete

- When all files are selected, do not send the whole file list
- Download will trigger download for the parent folder, also works
  with root
- Delete will send "allfiles" to the server that will find the file
  list or the passed directory by itself
LDAP: prevent other configuration from being deleted when deleting the first one which has an empty prefix for historical reasons