refs #80 - Sketch base GUI: create/draw point, circle and arc

refs #80 - Sketch base GUI: create/draw point, circle and arc

1. Split init(feature, feature) on init(feature), setFeature(feature, selection mode). The cause is lenght constraint.
2. Mouse double click signal listen by operation.
3. Correct displayer to use the selection mode only in activateInLocalContext method. It was temporary realized in the redisplay().
4. Increase selection tolerance for dimension text.