refs #2465

 * row evolution and transitions can be launched from the sidebar
 * when launching overlay, always pick date "current month"
 * make sure there never are two scrollbars when the window is not high enough

git-svn-id: http://dev.piwik.org/svn/trunk@7473 59fd770c-687e-43c8-a1e3-f5a4ff64c105