Latest and greatest! New UI! New markers! 2-port calibration!

Today's release (Yes, it really is daily at this point) has a bunch of new features, a new layout, and a better internal structure to support "pip" for installing.

A mouse-controlled marker is now available, and all markers have a Better graphic to show them more clearly.

2-port 1-path calibration is now available in the application, and calibrations can be saved and loaded.

The UI has been changed in an attempt to further adapt for small screen users.

I thank Ohan and Olgierd, who have both contributed code to this release.