fix for https://github.com/eXist-db/dashboard/issues/29
Merge pull request #30 from dizzzz/fixes

fix for https://github.com/eXist-db/dashboard/issues/29
Removed 'rest/db' from retrieve-backup-url
Merge pull request #31 from zwobit/master

Fix for download of zipped backup not working
Merge branch 'master' of https://github.com/eXist-db/dashboard