Make newline after examples table optional
Refactor to allow mocking of file generated when printing a feature
Add `ExamplesTable` to AST
Add `TableRow` to AST
Add test verifying presence of examples table on Scenario Outline
Use `AST::ExamplesTable` and `AST::TableRow` in Gherkin parser
Test that "Examples:" is parsed as a keyword
Add visitor for determining the correct width for columns in tables
Allow steps with doc strings or data tables to be followed by other steps
Add printing visitor for printing ASTs

Using a visitor is the recommended way of traversing an AST (it's also the example used for the visitor pattern in Design Patterns).
Use PrintingVisitor for GherkinRuby.print method
Add feature file that uses scenario outline