Dispatcher#statistics: updated to include at least a 'node' key to avoid nil errors
* Added notifications for some WebUI controller actions -- which also double as an activity log
* Front page is now a dashboard with an activity and notification list/log
Refactored Issue to include more vuln data

The new extra data are In addition to the summary data
provided by the RPC #progress method and are to be filled
once we get our hands on the final report.
Updated CanCan Ability for Notification models
application.js: activeAccordionGroup cookie now uses path '/'
bundle update
Added scaffold_controller for Issues and the ability to show individual Issues
-- => &mdash;
ScansController#update: added Notification when sharing a scan