Retrieve activity granularity

[doublejosh]

Changes:

Allow more fine grained activity lookups...

groucho.getActivities('watch', [
  {'videoType' : ['tutorials']}
]);

groucho.getActivities('formSubmit', [
  {'formId' : ['site_search', 'support_search']}
]);

groucho.getActivities('browsing', [
  {'entityType' : ['blog', 'visualization']},
  {'category' : ['social-content']},
  {'author' : ['555', '123', '999']},
]);

To Do:

• Tests for all forms of lookup. Branch now down to 71% coverage.