Dynamically set page title subheader.

 On branch page_header
	modified:   app/assets/javascripts/backbone/lib/components/page_header/show/show_controller.js.coffee
	modified:   app/assets/javascripts/backbone/lib/components/page_header/show/show_view.js.coffee
	modified:   app/assets/stylesheets/components/page_title.css.scss