DG RY; provide a background color to post author for legibility on post pages with background images

pjax clicking on nav arrows; move author header into backbone land; comment out comment form for now

the previous and next posts are now supplied in json of the presenter; give the template creator a default value

Go to root page if deleting post from the show page

Conflicts:
	public/javascripts/app/router.js
	public/stylesheets/sass/application.sass