This reverts commit 8e667d19.

Fix #7166

Fix issue #7166

Fix issue #6920

When session_keepalive is true (default) the heartbeat will be send as
often as the half of the session timeout value.

- Refactored download URL building to make it overridable
- Added download URL override in public page
- Added JS unit tests for download URL
- Added OC.redirect() method to facilitate unit testing

Makes it possible to create query strings by passing a JavaScript hash
map and automatically encodes the keys and values.

As suggested by @PVince81 : https://github.com/owncloud/core/pull/6721#issuecomment-32289922

This fix issue of calendar app with IE8, see issue report for details:
https://github.com/owncloud/calendar/issues/291

Some apps might not define the same "nplural" value.
To avoid conflicts, the plural function is now generated per app.

Fixes #6427

On the update page, config.js was missing which caused oc_webroot to not
be available. That would trigger the faulty oc_webroot fallback that
didn't take URLs like "/owncloud/index.php/files/apps" into account.

This fix adds config.js in the update page and also a fix for the
oc_webroot fallback, in case it is used elsewhere.

- show tooltip when violating naming constraints while typing
- when target filename exists on server fallback to dialog to interrupt the users flow because something unexpected went wrong
- fixes #5062
- also fixes some whitespace and codestyle issues in files js
- uses css selector over filterAttr in touched js files

use places/folder icon,
move link construction to JS,
only show icon on hover,
use 'searchresult' as css class name,
add filter/unfilter methods,
highlight searched files in current filelist
only filter when correct FileList is present

Frontend:
- The files app list now uses ajax calls to refresh the list.
- Added support the browser back button (history API).
- Added mask + spinner while loading file list

Backend:
- Added utility function in core JS for parsing query strings.
- Moved file list + breadcrumb template data code to helper
  functions
- Fixed some file paths in trashbin app to be similar to the files app

refactor OC.Breadcrumbs, allow injection of container to allow rendering crumbs into full screen editor