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
Trashbin select all now doesn't send file list

- Fixed "delete" and "restore" actions to not send the file list when
  all files are selected
- When some files are selected, sends the current dir
- Removed "dirListing" attribute as the backend is able to compute the
  value based on the current dir
LDAP: improve compilation of filters
Merge pull request #7195 from owncloud/files-selectall

Do not send file list for select all on Download/delete
Fixed ext storage webdav path encoding

- Some WebDAV servers like lighttpd need paths in URLs to be properly
encoded
- Added error log output when curl connection failed
- Added check for 'resourcetype' in case the WebDAV server doesn't
  support/return it
- Fixed touch() to return false if the server doesn't implement
  PROPPATCH
- Added optional delay in WebDAV unit tests to use when testing against
  lighttpd's WebDAV
Merge pull request #7027 from owncloud/extstorage-webdavurlencodingfixes

Fixed ext storage webdav path encoding
Added extra checks for ext storage class
Optimize some images

and strip metadata from png images with optipng in image_optimization.sh
Merge pull request #7294 from owncloud/extstorage-configclass

Added extra checks for ext storage class
Merge pull request #7284 from owncloud/ldap_filter_compilation

LDAP: improve compilation of filters
Revert "Added extra checks for ext storage class"

This reverts commit 9e9a5b9ea1f9b4699cf2d0c621f3f911f3639df9.

Unit tests weren't ready, need further tweaking.
Merge pull request #7295 from owncloud/optimize_images_kondou

Optimize images
merge master