Check for blacklisted characters

fix filepicker home icon being partly hidden, fix #10169

Fixes https://github.com/owncloud/core/issues/11264

(This should in future get moved to the mountpoint class - but that is something for @icewind1991 ;-))

Do not show exception to the end-user - use a proper error page instead

Moved WebDAV check to client side JS

DragnDrop Upload text style

send browsers timezone back tp the server on login

Fix icon classes, disappeared delete icon

Fix share key pattern matching

Instead of inaccurate pattern matching, use the list of users who we
know have access to the file to build the list of share keys.

This covers the following cases:

- Move/copy files into a subfolder within a share
- Unsharing from a user
- Deleting files directlry / moving share keys to trashbin

Use only lower-case letters

Do only follow HTTP and HTTPS redirects

- Added setup checks in JavaScript
- Moved isWebDAVWorking to JS using SetupChecks
- Moved internet connection checks to an ajax call that goes through the
  server

remove post setup check

first check if a private key exists, if not it is always a recovery szenario

Use non-empty defaults for preview cmd line

fixing directory seperators

Fix autotest.sh for whitespace in paths

WebDAV now throws 403 when deletion did not work

Add a configuration switch for enabled preview mimetypes

Fixes https://github.com/owncloud/core/issues/11239

We do not want to follow redirects to other protocols since they might allow an adversary to bypass network restrictions. (i.e. a redirect to ftp:// might be used to access files of a FTP server which might be in a secure zone and not be reachable from the net but from the ownCloud server)

Get final redirect manually using get_headers()

Migrate to HTTPHelper class and add unit tests

Revert "Travis support"

Added extra check to avoid deleting key folders

This reverts commit 472d896c.

Conflicts:
	.travis.yml

Reenable file proxy when renaming between mount points

Fix oc stream seek