Graphics for SEP MultiStar
Add some graphics on the guider's fitsview to give the user some visual intuition about the multi-star guider. It shows the "neighbor stars" and indicates (in red vs green) whether or not they were associated. Introduces a GuideView class which is a descendent of the FitsView, with just the added methods to draw the new overlay. This commit only has effect if the user is running the multi-star guider, and then only changes the visuals. To test, run the multi-star guider in the simulator. You should see a reticle around the main guide star and green/red circles around up to 9 neighbor stars, with lines connecting the guide star and its neighbors.