Document World bounds and Grid bucket size.

Added jsdoc comments for the following properties:

- `world.bounds`
- `grid.bucketWidth`
- `grid.bucketHeight`

src/body/World.js

@@ -85,6 +85,14 @@ var Common = require('../core/Common');
      * @default 0.001
      */
 
+    /**
+     * A `Bounds` object that defines the world bounds for collision detection.
+     *
+     * @property bounds
+     * @type bounds
+     * @default { min: { x: -Infinity, y: -Infinity }, max: { x: Infinity, y: Infinity } }
+     */
+
     // World is a Composite body
     // see src/module/Outro.js for these aliases:
 

src/collision/Grid.js

@@ -34,6 +34,22 @@ var Common = require('../core/Common');
         return Common.extend(defaults, options);
     };
 
+    /**
+     * The width of a single grid bucket.
+     *
+     * @property bucketWidth
+     * @type number
+     * @default 48
+     */
+
+    /**
+     * The height of a single grid bucket.
+     *
+     * @property bucketHeight
+     * @type number
+     * @default 48
+     */
+
     /**
      * Updates the grid.
      * @method update