Adding test:ci:clean task
Added updated gemfile
Locking down Firefox version to 23 to support selenium-webdriver 2.35, which is required by the Ruby 1.8.7 tests
Merge pull request #68 from appfolio/lockdownFirefoxVersion

Lockdown Firefox version
Wrapped Capybara::ElementNotFound error in AePageObjects::LoadingElementFailed so that ElementProxy#presence can handle the case where locating the element succeeds but the load ensuring checks fail.