Merge branch 'dev' of https://github.com/mrdoob/three.js into dev

docs/api/extras/helpers/GridHelper.html

@@ -29,7 +29,7 @@
 		<h3>[name]([page:number size], [page:Number step])</h3>
 		<div>
 		size -- The size of the grid <br />
-		step -- The size of the step btween 2 lines 
+		step -- The size of the step between 2 lines 
 		</div>
 		<div>
 		Creates a new [name] of size 'size' and with steps of size 'step'.