fix typo

docs/api/math/Vector2.html

@@ -103,7 +103,7 @@
 		Computes length of this vector.
 		</div>
 
-		<h3>[method:Float lengthManhatten]()</h3>
+		<h3>[method:Float lengthManhattan]()</h3>
 		<div>
 		Computes Manhattan length of this vector.<br />
 		[link:http://en.wikipedia.org/wiki/Taxicab_geometry]

src/math/Vector2.js

@@ -337,7 +337,7 @@ THREE.Vector2.prototype = {
 
 	},
 
-	lengthManhatten: function() {
+	lengthManhattan: function() {
 
 		return Math.abs( this.x ) + Math.abs( this.y );
 	},