Open geo: URIs from other apps

- Launch Adresilo directly from `geo:` links (e.g., geo:latitude,longitude or
  geo:0,0?q=query). This allows Adresilo to be a searching shim between, for
  example, calendar events with loosely-defined locations and navigation apps
  that might work best with coordinates.
- If only a search query is provided (e.g., geo:0,0?q=Eiffel Tower), Adresilo
  will automatically perform a search for that query and display the results.
- If coordinates are present in the link, Adresilo will display the location
  details without querying the server. If a name is included (e.g.,
  geo:lat,lon?q=Location Name), it will be used as the place name.
