Revert "WIP: Replace the session gem with PTY"

This reverts commit db30b5de587ad64fccd6987fa2b972d9fd89c81b.
Show more output when running tests

Travis will kill the test run if it doesn't see output for 10 minutes. This
seems to be happening when running the Rails integration tests in particular.
The only real way to solve this is to just show more output.

Also ensure RSpec formatters are flushing output after each test is run so that
Travis sees output as soon as it is generated.