Fixed a bug that class selectors set in the top level of the `class` argument for fields got inserted in all type of field containers including `fieldrow`, `fieldset`, `fields`, `field`. Fixes #164.
- Refactored the jQuery plugin script.
- Made the top level items in the `attributes` argument array apply to the `select` tag.
Added an example of nested revealer fields, which also demonstrates the use of the `class` argument for fields.
- Advanced the version number.
- Generated the minified version to reflect the change.