add additional screenshots

git-svn-id: https://plugins.svn.wordpress.org/bugherd-dashboard/trunk@901939 b8457f37-d9ea-0310-8a92-e5e31aec5664
add screenshots to trunk

git-svn-id: https://plugins.svn.wordpress.org/bugherd-dashboard/trunk@901941 b8457f37-d9ea-0310-8a92-e5e31aec5664
adjust readme

git-svn-id: https://plugins.svn.wordpress.org/bugherd-dashboard/trunk@901947 b8457f37-d9ea-0310-8a92-e5e31aec5664
add screenshot descriptions to readme

git-svn-id: https://plugins.svn.wordpress.org/bugherd-dashboard/trunk@901949 b8457f37-d9ea-0310-8a92-e5e31aec5664