- fix problems on linestitch interactive creation

- add creations function
- change functions in joincurve class to insert new curves anywhere and remove them
- add an action to create and add a subcurve to a joincurve

- add some actions to clear selections

- add a toggle close function for last selected curve (C key)

- add editLastAction function to OE_controller to make possible "live modification"
- add OE_actionSetPointCurve and OE_actionMovePointCurve to OE_actionCurves
- add setPoint function to OE_pointcurve and change getPoint to use reference instead of pointer

- create an actionSelection only when there is a selection

- improve selection mode to create only one action for each clic
- fix problem on delete of some stiches