Moves screenshots from trunk to assets.

Adds ability to show or hide testimonial images via a shortcode attribute.

Displays the proper shortcode to output testimonials by category, in the table of testimonial categories.

git-svn-id: https://plugins.svn.wordpress.org/easy-testimonials/trunk@842631 b8457f37-d9ea-0310-8a92-e5e31aec5664