Atom Title Truncation Patch

Hi Amber,

This is my first fork/pull request on GitHub and I'm also not a python user, so forgive anything astray. As mentioned on G+

https://plus.google.com/106279460080971988945/posts/h4BzG9DTugD

This is my patch to truncate a post title at the first <br /> tag. That seems cleaner to me than having it run on for 100 characters across paragraphs, and it allows for one to create a title on the G+ post and then have it appear in the atom exactly as that, which makes any downstream use (in particular, writing it to Wordpress) closer to intended.

I tested the regex code by dropping it in to a test program and giving it a variety of input. I don't have a simple way to test this in situ, so the logic has been tested but my dropping of it into the context of your program has not.