add gear generator to mesh tool

src/geo/polygon.js

@@ -992,6 +992,20 @@ class Polygon {
         return this;
     }
 
+    /**
+     * @param {int[]} verts flat array of x,y,z vertices
+     */
+    addVerts(verts) {
+        for (let i=0; i<verts.length; ) {
+            this.add(
+                verts[i++],
+                verts[i++],
+                verts[i++]
+            );
+        }
+        return this;
+    }
+
     /**
      * append point to polygon and return point
      */