Fix delegate calls

Make sure to call both the will/did AddAnnotations delegate methods, not 'willAddAdditions' twice

Signed-off-by: Blake Skinner <bskinner@mit.edu>
Fixes - [MapView addAnnotations:]

Fixes the bug where the addAnnotations: method would not add the annotations to the set. Also clean up the annotation mutation process in general.

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