Structured post formats: Image

* Adds 'image' to the array of structured post formats.
* Sets the content width to 650px. This should have been changed when
the content area width was changed in 1.5
Change the get_the_url() call to get_the_post_format_url();

http://core.trac.wordpress.org/changeset/23899/trunk changed the
function names.
Add the shortcode_atts_{$shortcode} filter to the shortcodes

New 3.6 filter. See
http://markjaquith.wordpress.com/2013/04/04/wordpress-36-shortcode-attribute-filter/

This also changes some of the formatting.