(3) Added number labels to coregister_landmarks when choosing landmarks; Moved the GUI code for the lung segmentation and SNR to a new function "updatePanelOverlay". The purpose of this was to fix errors by many different functions competing to update the image panels. This function can be used whenever temporary modifications need to be made to the image panels, and should hopefully make it easier to add features in the future; Improved maskOverlay performance and prevented possible crashes.