fix #18 missing og data

 On branch master

	modified:   _content/2-blog/2013-06-12-pinfinity-ibooks-author-wishlist.md
	modified:   _content/2-blog/2013-07-06-weekend_reading_for_july_6_2013.md
blog post: download ibooks

 On branch master

	new file:   _content/2-blog/2013-07-14-medical-ibooks-need-more-downloads.md
	new file:   assets/figures/gallbladder-ibook-in-ibookstore.png
	new file:   assets/figures/medical-section-ibookstore-screenshot.jpg