Add support for specifying route transport mode.
Save route and maneuvers as soon as added.
Unify Map.add* arguments.

And make them more flexible for future additions.
Don't use hasOwnProperty.
Save POIS, route and maneuvers on clear.
Separate set_mode from set_route.
Add mode property for Route, for consistency.
Fix geocoding to zoom to recent results, not all POIs on map.
Document method argument.