add <tbody> tags to candidate tables
make candidate styles most specific
restrict textarea resizing on candidate comments
add AJAX backend for comment processing
Add new js lib: @modernizr.js
support and enable comment previews

Support comment previews by using jQuery, the AJAX backend
added in d51715ac and some central CSS classes and styling.
Put it in a new comments.js file and add a function to en-
able it. Enable it for reviews and candidates.

Also add HTML5 "placeholder" attributes for comment input
<textarea> elements.
use HTML5 for autocomplete user list

Use the HTML5 "list" attribute and <datalist> tag
for native support of the auto-complete user list.

Use modernizr.js to detect if the browser supports
that. If not so, still use the jQuery-UI solution,
but read the data from the document instead of an
AJAX request.