Help text

http://manage.dimagi.com/default.asp?130862#777250

http://manage.dimagi.com/default.asp?141280
Yeah, don't use `mug.ufid`. How about this?

Add this to `src/form.js` near [line 173](https://github.com/dimagi/Vellum/blob/help-text/src/form.js#L173)
```js
        getRootPath: function () {
            // the choice to use dataTree instead of controlTree is arbitrary
            return "/" + this.dataTree.getRootNode().getID() + "/";
        },
```

Then you can call `mug.form.getRootPath()`