Created Admin Fixtures to make testing easier.

* Fixtures are an easy way to automatically create records in the
  database before tests are run, reducing the amount of fiddling
  necessary to get tests to work.
  * I created a fixture for an Admin to make it easier to test editing
    and destroying an admin, along with requiring an admin to be
    logged in to access the admin section.
  * You can learn more about fixtures here:
  http://guides.rubyonrails.org/testing.html#the-low-down-on-fixtures
Add Test Helper methods to test controller permission restrictions

* These helpers were pulled from another repository, and make it easy
  to check whether a resource is protected from external access by
  automating the tests and abstracting them into another module.
Create Admin "Dashboard", test that it's only accessible to admins

* The Admin Dashboard is the "home page" for the admins section.
  * Provides useful links outside the application, along with links to
    manage galleries and pages.
* First instance of using the Permission Restriction test helpers
  added in 27137b2