Spline\Polyline entities: fixed the defect when the control point is selected, moved outside the document area and becomes unreachable.

Added the menu item   MainMenu>Trace>MagTrace

Implemented a support function to output the Edges used by MagTrace for the current slice.
Currently selected MagTrace parameters are used so it is a 1-click operation.

Corrected the "HitTest" on mouse click over the Spline entity.

Corrected the defect for the HitTest mouse click on the polyline.

Modified the ToolTip for the "Width\Level" button of the Main toolbar.