Gulri slider screenshots description added.

git-svn-id: https://plugins.svn.wordpress.org/gulri-slider/trunk@1011932 b8457f37-d9ea-0310-8a92-e5e31aec5664
Demo URI added now.

git-svn-id: https://plugins.svn.wordpress.org/gulri-slider/trunk@1011936 b8457f37-d9ea-0310-8a92-e5e31aec5664