Adds a vertex to the hull
function(eyeVertex) {
      var horizon = [];

      this.unassigned.clear();

      // remove 'eyeVertex' from 'eyeVertex.face' so that it can't be added to the 'unassigned' vertex list

      this.removeVertexFromFace(eyeVertex, eyeVertex.face);

      this.computeHorizon(eyeVertex.point, null, eyeVertex.face, horizon);

      this.addNewFaces(eyeVertex, horizon);

      // reassign 'unassigned' vertices to the new faces

      this.resolveUnassignedPoints(this.newFaces);

      return this;
    }