replaced Array.prototype.push.apply to avoid hitting stack size limit…

… on larger arrays.

src/grid.js

@@ -33,7 +33,11 @@ Grid.prototype = {
 
         for (let x = tlCellX; x <= brCellX; x++) {
             for (let y = tlCellY; y <= brCellY; y++) {
-                Array.prototype.push.apply(points, this.cellPoints(x, y));
+
+                // replaced Array.prototype.push.apply to avoid hitting stack size limit on larger arrays.
+                for(let i = 0; i < this.cellPoints(x, y).length; i++){
+                    points.push(this.cellPoints(x, y)[i]);
+                }
             }
         }