Add a show/hide toggle for the post contents, hidden using JS on load.
Add a link to the `/archive` URL generated by Tumblr.
Photo thumbnails on index pages are links.
Merge branch 'master' into tumblr

Conflicts:
	web/index.html
Apply CSS from `master` branch.
Position featured media with its own margins, not nearby heading's.
Merge branch 'master' into tumblr
Apply CSS from `master` branch.
Tweak margins on headings for a slightly tighter layout.
Merge branch 'master' into tumblr
Apply CSS from `master` merge.