Optional text URL linkification

Closes #102.
Embed YouTube and Soundcloud links with HTTPS

Addresses #100.
Remove bogus var
Parse string, not array
Open mailto links in a new tab

Prevents webmail clients from replacing tab content.
No effect on traditional email clients.
Auto-determine global theme version

Based on the theme.css?v=X URL. Closes #103.
Merge remote-tracking branch 'upstream/master'

* upstream/master:
  Auto-determine global theme version
  Open mailto links in a new tab
  Parse string, not array
  Remove bogus var
  Embed YouTube and Soundcloud links with HTTPS
  Optional text URL linkification

Conflicts:
	common.js
	tmpl/index.html