An improvement for the sketch operation restarting mode change.
The operation should be restarted in the following cases:
1. There are no more widgets in the property panel,
2. If the vertex is selected beforehand the first case happens, the operation should not be restarted(ForbidRestarting)
3. During the operation commit the restarting flag is analized to perfrom the restart if necessary.
4. Enter button release should restart operation but the previous feature is not concidered.
