Adds "testing" Scenarios and FunctionalFeatureContext methods

- Adds Scenarios
    - A GET request with some query string jargon
    - Sending data along with a POST request
- Adds FeatureContext methods
    - @Given I have some data to send:
    - @When I send a POST request to :uri
    - @When the response entry :field_name should be :contain_value
Implements GET/POST "testing/echo" w/ data. Routes/Ctrlr/Formatting