Urlencode file name before passing it to cURL

Large file helper use cURL to determine file sizes. Thus filenames must be
urlencoded in case special symbols like '#' can cause BadRequest errors.

Signed-off-by: Tony Zelenoff <antonz@parallels.com>
apply @carlaschroder's changes from owncloud/documentation#594
Additional changes to config.sample.php and typo fixes
Merge pull request #11486 from owncloud/config-update

Config update
[tx-robot] updated from transifex
Merge pull request #11501 from Ansud/master

Urlencode file name before passing it to cURL