Revert "Add userData to Geometry"

This reverts commit 2928e097a2050675791e449345a7826a9ccaa20b.

src/core/Geometry.js

@@ -46,8 +46,6 @@ function Geometry() {
 	this.boundingBox = null;
 	this.boundingSphere = null;
 
-	this.userData = {};
-
 	// update flags
 
 	this.elementsNeedUpdate = false;
@@ -989,7 +987,6 @@ Geometry.prototype = Object.assign( Object.create( EventDispatcher.prototype ),
 		data.uuid = this.uuid;
 		data.type = this.type;
 		if ( this.name !== '' ) data.name = this.name;
-		if ( Object.keys( this.userData ).length > 0 ) data.userData = this.userData;
 
 		if ( this.parameters !== undefined ) {
 
@@ -1418,10 +1415,6 @@ Geometry.prototype = Object.assign( Object.create( EventDispatcher.prototype ),
 
 		}
 
-		// user data
-
-		this.userData = source.userData;
-
 		// update flags
 
 		this.elementsNeedUpdate = source.elementsNeedUpdate;