Switch from direct ivar accesses to properties and perform some cleanup to prepare for the ARC conversion.

Signed-off-by: Blake Skinner <bskinner@mit.edu>
Fix an incorrect link in the XIB

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

Signed-off-by: Blake Skinner <bskinner@mit.edu>
Fix the center offset for a bus' location annotation. We should have added 3 (move down) instead of subtracting (moves annotation up)

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