Hiding next/previous arrow on first/last photo. #1391 Closes #1478

Conflicts:
	src/html/assets/themes/fabrizio1.0/config/settings.ini
	src/html/assets/themes/fabrizio1.0/javascripts/op/Lightbox.js
	src/html/assets/themes/fabrizio1.0/stylesheets/less/components/lightbox.less