Twenty Eleven: Add whitespace to paragraphs in the image post format.

[mfields]

Here's what the image post format looks like when a captioned image is followed by a paragraph:
​https://img.skitch.com/20120417-1beqfrrscbwcy7rtwxn2msqs69.png

The attached patch will adjust the whitspace allowing content to be displayed between the image and meta content if present in the post_content:
​https://img.skitch.com/20120417-f2jr8h6qtyuxj6nr5x6ea538n7.png

The patch also fixes a disply issue in the media queries for the image format where float is set to none in .alignleft and .alignright but the elements are not explicitly set to block-level.

[nacin]

In [20905]:

Twenty Eleven: Add whitespace to paragraphs in the image post format. props mfields, fixes #20471.