Added acceptance testing with RSpec.

* rspec+capybara dependencies.
* Stub out the specs.
* Specs are talking to the server.
* Connect to a sandboxed test Ivanhoe.
  - Database dump.
  - Spec that the theme is installed.
  - Spec configuration.
  - WP configuration isolation.
  - Database configuration isolation.
* Pull test database settings from the environment.
Merge branch 'develop' of github.com:scholarslab/ivanhoe into develop