Update README.md

Include module enabling in installation instructions.
Merge pull request #30 from nhebi/master

Instructions to enable module in README.md
add legend and class to renderFieldset()
* Added `'wrapCheckboxInLabel'` option for the ability to wrap solitary checkboxes and label text inside a label, wrapped inside a `div.controls` element
* Made label for groups of radio buttons / checkboxes be rendered as `<div class="control-label">label text</div>`, since labels should only relate to one form element (not a group of them)
* Made `for` attribute on <label> only be rendered when form element has an `id` attribute (putting the element's `name` in the `for` attribute isn't valid)
* Moved the automatically-generated hidden <input> for solitary checkbox so it's rendered *outside* of the <label>
Merge pull request #33 from nhebi/fieldset-legend

add legend and class to renderFieldset()
Merge pull request #35 from rudidude86/master

Improving(?) the way labels and checkboxes are rendered
Merge pull request #34 from shaunfreeman/clean-master

added error colour to formElements