Undo/Redo

WYMeditor's undo is, in some cases, not accurate.
I love it. I just love it. CommonJS modules, distributed via NPM. If they are aimed at browsers (either explicitly or not) they can be browserified and then Bam! You get something you `require` in a browser.

In our case, we don't use any module system, so I solved it by throwing this module up into global, by use of this wrapper.