Set up the app to reset the system default browser on terminate (fixes #1) and install itself as the default browser on start if previously configured to be the default.
Merge branch 'feature/default-browser-only-when-running'

* feature/default-browser-only-when-running:
  Set up the app to reset the system default browser on terminate (fixes #1) and install itself as the default browser on start if previously configured to be the default.