fix(facade/lang): use strict equality for performance

Author: tbosch

modules/facade/src/lang.es6

@@ -12,11 +12,11 @@ export class IMPLEMENTS {}
 
 
 export function isPresent(obj):boolean {
- return obj != undefined && obj != null;
+ return obj !== undefined && obj !== null;
 }
 
 export function isBlank(obj):boolean {
- return obj == undefined || obj == null;
+ return obj === undefined || obj === null;
 }
 
 export function stringify(token):string {