Takes first pass at dynamic page header component.

 On branch page_header
	new file:   app/assets/javascripts/backbone/entities/abstract/page_header.js.coffee
	renamed:    app/assets/javascripts/backbone/entities/abstract/property-nav.js.coffee -> app/assets/javascripts/backbone/entities/abstract/property_nav.js.coffee
	modified:   app/assets/javascripts/backbone/lib/components/layouts/header_sidebars/header_sidebar_state_manager.js.coffee
	modified:   app/assets/javascripts/backbone/lib/components/layouts/header_sidebars/header_sidebar_view.js.coffee
	modified:   app/assets/javascripts/backbone/lib/components/layouts/header_sidebars/templates/layout.jst.hbs
	new file:   app/assets/javascripts/backbone/lib/components/page_header/page_header_app.js.coffee
	new file:   app/assets/javascripts/backbone/lib/components/page_header/show/show_controller.js.coffee
	new file:   app/assets/javascripts/backbone/lib/components/page_header/show/show_view.js.coffee
	new file:   app/assets/javascripts/backbone/lib/components/page_header/show/templates/show.jst.hbs