0.3 with libayatana-appindicator3

Migrate to ayatana-appindicator3-0.1

From the old appindicator3-0.1, which is deprecated, and conflicts with
the newest and greatest ayatana-appindicator3-0.1.

Check this for some more context:
https://github.com/AyatanaIndicators/libayatana-appindicator/issues/30