Better download UI/UX

[contrapunctus-1]

The map download interface is functional but quite rough at the moment. Please look at the download manager in Organic Maps for inspiration.

1. If a user has offline maps selected, opens a track, and there's no map data for that area, offer to download the map for that area.
   Extracted to Offer to download missing maps for an area #418

2. Use a native UI (as opposed to the current webview) to list maps for download.
   Extracted to Use a native UI (as opposed to the current webview) to list maps for download. #417

3. Download resumption does not seem to be supported. This is necessary for downloading large map files, such as India (1.3G), over unstable connections.
   Extracted to Use download manager for offline map #403

4. Notify the user when there are newer versions available for their downloaded maps. Ideally using a red dot to guide them to the updated maps, similar to Organic Maps.
   Extracted to Notification for updated map downloads #419

Thanks.

[pstorch]

I've extracted all feature requests into their own issues to better handle and track them.
Closing this issue.