fixing gallery most-viewed link
fixing gallery onward border-top colour
gallery/media margins
fixing show-info lightbox state
reload endslate properly
don't toggle info when info panel is clicked
info button highlighted when active
switch up/down buttons
jshint fix
changing gallery lightbox controls to <buttons> and changing focus style
using our template library
lightbox button text for accessibility
Merge pull request #5957 from guardian/gallery-styles

various gallery/lightbox fixes/tweaks