Added diff() to util.js
Added diff() to util.js

corinthia/corinthia-editorlib,corinthia/corinthia-editorlib,corinthia/corinthia-editorlib,corinthia/corinthia-editorlib,corinthia/corinthia-editor,corinthia/corinthia-editor,corinthia/corinthia-editor,corinthia/corinthia-editor,corinthia/corinthia-editor,corinthia/corinthia-editorlib