QuickHull3: Clean up

src/math/convexhull/QuickHull3.js

@@ -12,8 +12,6 @@ import { MergeNonConvexLargerFace, MergeNonConvex } from '../../constants';
  *
  */
 
-var c = 0;
-
 function QuickHull3() {
 
 	this.tolerance = - 1;

src/math/convexhull/VertexList.js

@@ -78,7 +78,7 @@ Object.assign( VertexList.prototype, {
 
   },
 
-  // Appends a 'node' to the end of this doubly linked list
+  // Appends a vertex to the end of this doubly linked list
 
   append: function ( vertex ) {