Align the WP.com stats smiley :)

This fixes an issue where the stats pixel was loading in the very
bottom left of the page. Much better to have it center aligned.
Move post-meta in to minimal_stream_meta(), should fix #2

This moves the post-meta below the main content of a post and merges
the date and tags in to a single function. Props @danielbachhuber.
Adjust the font-size of navigation

With the sans-serif font stack we now don't need as large of a
font-size.