private pairLinkLink cutLink(Link toCut,MutableCoord p){
  Node endPoint=getRandomNode(p);
  net.addNode(endPoint);
  pairLinkLink pair=fixLink(toCut,endPoint);
  diffManager.saveState(null,DifferenceManager.type.CREATE,endPoint,null,pair.link1,pair.link2,null,null,activeLink,null);
  controls.updateButtons();
  controls.updateTable();
  return pair;
}

private pairLinkLink cutLink ( Link toCut , MutableCoord p ) { Node endPoint = getRandomNode ( p ) ; net . addNode ( endPoint ) ; pairLinkLink pair = fixLink ( toCut , endPoint ) ; diffManager . saveState ( null , DifferenceManager . type . CREATE , endPoint , null , pair . link1 , pair . link2 , null , null , activeLink , null ) ; controls . updateButtons ( ) ; controls . updateTable ( ) ; return pair ; }
splits a link l in the coordinate given by p .
