Updated Usage Code in Readme - (fixed depthMax)

I spent a few hours trying to figure out what I was doing wrong - only to find out that "depthMax: -1" should now be "depthMax: Infinity".

README.md

@@ -57,7 +57,7 @@ Download the [minified script](https://github.com/collinhover/threeoctree/blob/m
 var octree = new THREE.Octree({
 	radius: radius, // optional, default = 1, octree will grow and shrink as needed
 	undeferred: false, // optional, default = false, octree will defer insertion until you call octree.update();
-	depthMax: -1, // optional, default = -1, infinite depth
+	depthMax: Infinity, // optional, default = Infinity, infinite depth
 	objectsThreshold: 8, // optional, default = 8
 	overlapPct: 0.15, // optional, default = 0.15 (15%), this helps sort objects that overlap nodes
 	scene: scene // optional, pass scene as parameter only if you wish to visualize octree
@@ -170,4 +170,4 @@ function onClick ( event ) {
 
 *Copyright (C) 2012 [Collin Hover](http://collinhover.com/)*  
 *Based on Dynamic Octree by [Piko3D](http://www.piko3d.com/) and Octree by [Marek Pawlowski](pawlowski.it)*  
-*For full license and information, see [LICENSE](https://collinhover.github.com/threeoctree/LICENSE).*   
+*For full license and information, see [LICENSE](https://collinhover.github.com/threeoctree/LICENSE).*