createCircle method
Creates a CW circle around a point
Implementation
void createCircle(Coordinate p) {
// add start point
Coordinate pt = new Coordinate(p.x + distance, p.y);
segList.addPt(pt);
addDirectedFillet(p, 0.0, 2.0 * math.pi, -1, distance);
segList.closeRing();
}