LPS-46221 Improve caretIndex calculation after insertion

Hey @natecavanaugh,

As you correctly guessed, we were missing the `body` tag as an ascendant. I was usually testing it by editing an existing entry, so I missed that case :cry: 

![ckeditor](https://cloud.githubusercontent.com/assets/905006/2927225/45f8f9de-d768-11e3-9a39-b491574c5645.gif)

_I'm basically, just writing in the editor (also, is this supposed to work in other CKEditors, like wiki and what not? It doesn't seem to running at all, in case it was)._

For now, based on the hook you're using, it should work only on those places that require `ckconfig.jsp`, since that's the one we're hooking onto, so in Wiki when using Creole, it shouldn't work. We'll work on monday on the hook part of this story, to see in which portlets and under which circumstances this is activated, so for now that's just so that we can test it. 

/cc @ipeychev 

PS: I've checked and it's working up until IE9. I've filed https://dev.ckeditor.com/ticket/11925 which is what we're hitting in IE8.