Adjust UI for guide tab. New info line display for internal guider.

Two main changes. (1) Tightened up the display on the guide tab; the read-only tables on the lower left side, and the circles around the reference stars in the image display. (2) Added a GuideInterface signal to add more more info display line on the lower left. The only guider that takes advantage of this now is the SEP MultiStar guider, which will print out a line looking like this: "Detections. 20 stars, 12/14 references". Other guiders could later take advantage of this additional info line. A screenshot of the UI used with SEP MultiStar after this change can be seen here https://photos.app.goo.gl/ucampKFG169b4hDa8 and before the change here https://photos.app.goo.gl/syKLJbfPRvT7RmVX9