Loading bar at the top

[Mondei1]

It would be nice I think to implement a small loading bar at the top on the page when data is fetching from the backend or the user has started a download.

Like that what you have here on GitHub.

[ghost]

Some loading-animation must be chosen, yes :)
But maybe we should choose some loading-circle instead, because this is what mose home-users will understand.
A hughe loading-circle that blocks the user from doing other stuff, is maybe better to prevent the user from clicking somewhere else because he doesn't understand the loading-bar at the top.

[Mondei1]

If a user sees a loading bar at the top and we make everything a little bit gray, he know that something is loading and he shouldn't do anything.