Ignore .DS_Store files (proprietary OS X files for „desktop services“)
Add everything that’s required to run tests through a headless browser:

- add gems capybara with poltergeist driver, as well as a gem that 
  integrates all (minitest-rails-capybara)
- new rake tasks „test:features“ and  „test:without_features“.
- the default rake task first runs test:without_features then features
- add one simple feature test for successful login
Merge branch 'master' of github.com:typus/typus into capybara
Let’s try to build the capybara branch on TravisCI. It should use PhantomJS 
for the feature tests.
Adapt two tests which failed after the flash message on toggle was removed.
Merge pull request #445 from typus/capybara

Add everything that’s required to run tests with a headless browser