Display CiviMember and CiviContribute dashboard elements.

Display CiviMember and CiviContribute dashboard elements.

* CRM/Memberdashboard/Page/MemberDashboard.php (__construct): Assign the
  result of 'loadContact'.
  (loadContact): Return the contact rather than assigning it to a
  variable.
  (buildDashboard): Return an array with CiviMember and CiviContribute
  dashboard elements.
  (pageTitle): New method.
  (run): Use 'pageTitle' method.  Assign dashboard elements for rendering.
* templates/CRM/Memberdashboard/Page/DashboardElement.tpl: New file.
* templates/CRM/Memberdashboard/Page/MemberDashboard.tpl: Render
  CiviMember and CiviContribute elements.