ui: Fix message in oops screen
Move hidden file skipping from monitor to thumbnailer

This allows other components to monitor hidden files.
albums: One go format fix
Add basic access control

For now, albums can only be private or public (they are private by
default). The framework for having more fine grained ACLs is in place,
but we don't have a way to authenticate a user yet.
Remove the Vagrantfile

We use Docker to make cross-builds now, the Vagrant setup is out of date
and not maintained anymore. See the README for more information.