Description
Refactor how Distances are added. With this MR we can click and drag to add distance. Note: The removal hasn't been modified. We still need to use SRemoveDistance.
Closes #1014
How to test it?
Launch SightViewer Load an image (DICOM for example) Click on "add distance" icon, the cursor should change to from a pointer to a cross, allowing you to click and drag and add a distance to the image
try to see if the distance is also displayed ton the different 2d negatos