Supports to show tags, but currently disabled.
Drop support for Python 2.5
Avoid duplicated --where warnings and slightly weird behaviour w/ nosetests runner.
Make tests runnable w/ py.test
Various improvements w/ ScenarioOutline:
 * name annotation in generated Scenario names
 * support placeholders in names of generated Scenarios
 * support placeholders in tags  of generated Scenarios
 * file location refers now to example/row.