Add no-redirect safety nets to contact/resume.

(contact, resume)/index.html
	-Add safety-net links to the contact/resume pages for browsers
	with automatic redirection disabled.
Add margin between comments and page footer.

_layouts/post.html, css/post.sass
	-Add a margin between page comments and the bottom of the page.
Restart nginx on site build.

post-receive.sh
	-Add a line to restart nginx once the site's compiled and in
	place.
Add files.sevko.io nginx server for static files.

nginx.conf
	-Add a separate server for static files.
Remove all binary data files.

downloads/prime_number_spirals.zip, img/**
	-Remove all binary data files from Git to prevent bloat.
	-The nginx server added in d2e71aa will contain all such files
	from now.
Update thumbnail links.

_includes/post_summary.html, articles/feed.xml
	-Update thumbnail links to point to files.sevko.io. See 8e67fa1.
Define static tag for creating full file URLs.

_plugins/static.rb
	-Create a custom Jekyll tag for converting file paths in blog
	posts to their full URLs (under `files.sevko.io`).

_posts/2014-10-01-prime-number-spirals.md
	-Replace full file URLs with much shorter versions using the
	`static` tag.
Merge github.com:sevko/sevko.github.io