* Add Vim modeline comments to all relevent template files.
* Add Vim modeline comments to a few other files.
* Move modeline comments inside the template definitions in list and single.
For some odd reason, putting them outside breaks the page generation.
* Use template comments for modeline comments in templates.
* Fix form 2 modelines.
Instead of writing my own logic for metadata and Twitter cards, I
should be using Hugo's own. This makes my theme code cleaner, but
means I have to adjust some of the configuration conventions that
I have been using. An added bonus is that my theme will work with
more sites now, as long as they are using Hugo's config conventions.
I had added Google Webmaster verify support but it got lost when I
was re-organizing the head meta stuff. I'm adding it back now plus
support for Bing and Yandex.