Undo after switching Bezier → Orthogonal causes reshaped link to lose endpoints

[walter]

GoJS 3.1.5 released

Changes for 3.1.5 Fixed undo of setting Link.curve to or from Bezier curve. Fixed object picking within the Diagram viewport when the viewport has been updated but not yet redrawn (for example in a “ViewportBoundsChanged” DiagramEvent listener). Fixed LinkReshapingTool not to allow resegmenting when the Link.curve is Bezier unless Link.isOrthogonal is true. Fixed Picture.source setter not updating the Picture measurements.