Added chrome.windows.onFocusChanged listener that finds the active window's active tab and reports on it as respondToTabActivation does. Updated respondToTabActivation to store activeTabId and reportOnVisitItems to use activeTabId when changing button and title. Fixes problem with all windows' extension buttons changing when a tab changes in one button.
Noted today's visits in mouseover along with all-time visits to avoid confusing.
Version bump.