Remove Fx firstrun test. Bug 877202.

- Removes images, CSS & JS files, & templates.

- Class-based view remains for later use.

- Updated class-based views & tests to use/expect a list
  of template names (conform to django intention)
Merge pull request #1753 from jpetto/bug-877202-remove-fx-firstrun-tests

Remove Fx firstrun test. Bug 877202.