Add pending step definitions for input feature
Fulfill step 'I have not started a session'

This step is empty, since the session has not been started.
Define and fulfill step "When I start a session..."

* Define the step: instantiate new Session with file
* Create RecordParser::Session class
* Configure Cucumber env.rb to load RecordParser::Session
Define remaining steps of "input file" scenario

* Define Output class and instantiate @fake_output cucumber collaborator.
* Define "Then I should see..." steps
* Alter RecordParser::Session to initialize with input and output