Grab next two posts when user scrolls to page bottom

When the user scrolls to the bottom of the page, instead of clicking the 'Moar
Posts' button, will simply be given the next two posts. This also removes the
behavior the auto scrolls the user to the top of the new posts, as the new
posts may load before the reader is done reading the current post.
Add separate copy of wall_of_code.png to /blog

After switching to Nginx from Apache, /blog was having trouble loading
wall_of_code.png from the parent directory. This simply copies the image to the
blog directory.