style(lists): Add new 'list' and 'item' classes for easy list styles

BREAKING CHANGE: This removes the default 'ol' styles for modal forms.
To keep the decimal list look, add a 'list' class to the `<ol>`
Merge pull request #371 from rackerlabs/262-modal-style

style(lists): Add new 'list' and 'item' classes for easy list styles