remove bundler from Gemfile to make travis happy (and because it's probably a good idea to do so)
revert previous commit (add bundler to Gemfile again) and try `with_clean_env`
use system call rather than backticks in order to see streamed output
simplify test code and rename rake task to integration_test
fix syntax error
fix misspelled rake task
intentionally test failure and see if travis build fails
fix failing build
update CHANGELOG