title: d3 time series tick format; displaying formatted labels, but preserve underlying date in clicks
body: <p>I've got a timeline that needs to display some counts for every hour in a day. The <code>x</code> data is something like <code>[10/01/2000 00:00, 10/01/2000 01:00, ...]</code>.  In the interest of keeping my x ticks legible, I'd like to drop the <code>10/01/2000</code> part of the string, <em>but</em> the data comes in as a full date, and I also need to keep that full date when I click the bar.  Is there a way to accomplish this?</p>