RSpec 3 updates.

- [x] Update specs and dependencies for RSpec 3.
- [x] Bypass install template override for Travis.
- [x] Includes a monkey patch for stub_authorization! (has created pull request for this https://github.com/futhr/spree_auth_devise/commit/0824cd5073ec0d8d9b87d1deddbf966fc401c4f8).