- store the len value of the birailStitch
- add the move function to staticStitch
- add getStitchStart and getStitchEnd method to OE_linkstitch
- fix a bug in OE_linkstitch::refresh method (it always put needRefresh to false)
- add double point motif to OE_linestitch
- add OE_actionDelStitch
- fix a bug in refreshDependency of most stitches and curves (does not refresh dependency of their own dependency)

- add actions for moves
- add - operator to vector_2d class

- add some actions to clear selections