Raising the Poltergeist timeout from 60 to 180 when in the 'CI' environment (Travis) to try to avoid failures due to Capybara::Poltergeist::TimeoutErrors.
Removes the `retry_on_timeout` defined under spec/features/.
Merge pull request #509 from afred/retry-poltergeist-timeout-failures

Raising the Poltergeist timeout from 60 to 180 when in the 'CI' environm...