Use circular toggles for airplane mode and ethernet

[danirabbit]

Fixes #152 Uses circular toggle buttons instead of modelbutton rows for airplane mode and wired items

Putting wireless here would require a significant rework, so it will have to wait for another branch

BEFORE

AFTER

With 1 ethernet port

With no ethernet

With lots of ethernet

In Greeter mode with no ethernet

[tintou]

I do wonder if we do not want to limit it to 2 circles wide with a Gtk.FlowBox?

[danirabbit]

@tintou I was just changing it to a flowbox since those other branches were merged ;)

Hows 3?

[tintou]

3 looks great :smiley:

[danirabbit]

@tintou found a bug with removing interfaces with the flowbox. Quick re-review? :)