- refreshing charts when the time interval changes
- saving last selection
- minimizing requests by using same query serial for frontend and backend queries
- fixed bug in dashboard's switch options for non-admins
- fixed Notice: Undefined index: ga_dash_frontend_stats for new installs 

git-svn-id: https://plugins.svn.wordpress.org/google-analytics-dashboard-for-wp/trunk@872974 b8457f37-d9ea-0310-8a92-e5e31aec5664