New Extension Capabilities in Karoo Release 1.538.2049

Expose navigation data in karoo-ext events:
- Current route (name, polyline, POIs, total distance)
- Current navigation destination
- Current reroute polyline (full polyline to destination, reroute polyline to return to route)
- Global POIs
- Map zoom level
Add karoo-ext effect to:
- Open pin activity to navigate to a destination
Add interface to show map items
- Show polylines with points and style
- Show icons at locations
- Extensions layer shows up in map layers list after first element is added
  - Extensions can be shown/hidden with map layer button