Adding automatic support for Google Universal Analytics event tracking, and some validation for both versions of GA. Removing node_type_view event, which ought to be tracked client-side.

Adding hook_wem_event_info for modules to declare WEM events they plan to track. This allows us to present admins with a full list of trackable events regardless of which events have already occurred (much more user-friendly). It will also facilitate better documentation. Implementing this new hook for all events tracked by the WEM module itself. Also adding a new pre-packaged event 'node_type_view.'

Fixed issues #2019311, #2019319, #2019313: Modified node type and user role variables to individual rather than a monolithic one to keep track of settings.

By donutdan4114: Updated report page to correctly display username of registered users and anon names for other people.