class-DB: settings: add duplicate option for graph

git-svn-id: https://plugins.svn.wordpress.org/feedly-insight/trunk@871738 b8457f37-d9ea-0310-8a92-e5e31aec5664
bump 0.9.7

git-svn-id: https://plugins.svn.wordpress.org/feedly-insight/trunk@871739 b8457f37-d9ea-0310-8a92-e5e31aec5664