1. Sketch solver invalid state: do not restart the create operation;
2. Line creation: several click in the same point: do not deactivate point widget if the feature already contains this value. [Scenario: start sketch, start line creation, click in the same place; create contour, create other sketch, click in the point on the 1st sketch to create a line. It is not possible]
3. Correction to call customizeCurrentObject only when some is displayed/erased. If this check is absent, there can be a crash. Scenario of the crash is: Create contour, make two lines paralle, make them perpendicular, Undo. Reason: created message of Sketch comes earlies than redisplay of perpendicular. SketchPrs_Perpendicular: getResult -> crash.
