adds some eager loading to the groups_controller

* this is probably not comprehensive but just what I noticed
bugfix to re-enable clicking "view all projects":

* adds missing open/close events to top menu
* removes select2's click filter as it masks our menu
Merge pull request #41 from opf/fix/groups_controller_eager_loading

adds some eager loading to the groups_controller
Improves check for api requests.

Timelines introduces a case where the json format is negotiated
but not represented in the format parameter via routes (i.e., the
extension ".json"). This change adds support for Accept-header content
negotiation, which results in the format field of the request. For
consistency, xml was also added.
Merge pull request #86 from opf/feature/better-api-request-check

Improves check for api requests.
Merge pull request #61 from opf/fix/select2-all-projects-squashed

bugfix to re-enable clicking "view all projects":