0.1.3/Make it visible when a group is loading

[misoe92]

Description.
When a group is loading it's currently not possible to see it in any way. Which is not that user friendly. Instead it should let the user know what is going on, and let them know that it's working.

Describe the solution you'd like
When a group is loading it should be clear, by fading out the current view and showing a spinner afterwards in it's place.

When everything is loaded the spinner should be faded out and the content should be faded in.

The fade should be a very quick fade, since we don't want to wait for it to finish, but still want the transition to feel smooth.