Activity summary view; dotstorm event fixes; more

Add a new activity summary view, which will form the basis of daily
activity summary emails.

Additional bugfixes:
 - Strip punctuation from phone numbers prior to validation (tests
   for xxx-xxx-xxxx and xxx.xxx.xxxx added)
 - Don't add "sharing changed" event to dotstorm unless the sharing has
   in fact changed. Add new utils.sharing_is_equal to check based on our
   logic whether two sharing objects are equal.
 - Change semantics of several event grammars.
 - Fix dotstorm schema URLs (spurious "=" prevented the virtual from
   being added properly). Add tests for URLs.
 - When adding/changing dotstorm "Idea" objects, as an optimization,
   only _id and sharing fields were fetched. However, this meant the
   slug that was needed to format the URL was missing, giving incorrect
   URLs for idea add/change events. Remove this optimization. Add tests
   for URLs on events.
 - Skip "rearranged" dotstorm events for now, as they duplicate idea
   add/change events unnecessarily. May re-add later when rearrangement
   is not accompanied by idea adding.