Add a reload method which tosses the list of cached annotations and reloads everything from scratch.

Signed-off-by: Blake Skinner <bskinner@mit.edu>
Annotation reloading after zoom

Reload all the annotations after the map view zooms in or out. All of the shuttle annotations should now work properly.

Signed-off-by: Blake Skinner <bskinner@mit.edu>
Annotation image generation

More cleanup in the image generation code for the Mapkit->ArcGIS bridge

Signed-off-by: Blake Skinner <bskinner@mit.edu>