RENAMED: basic_steps => generic_steps
Add more self-tests: background, select scenarios by tag
Add stdout_mode property to simplify usage in all (derived) Formatter classes.
Use stdout as default output stream again (was: stderr).
Formatter "sphinx.steps" to generate Sphinx docs for step definitions (related to: #166).
Provides basic functionality as sphinx.steps formatter (working prototype).
Minor code cleanup.
Update after stdout is used again.
Merge branch 'master' of https://github.com/behave/behave
NEW FORMATTER: sphinx.steps
Mark #166 as partly implemented. Basics of sphinx.steps formatter work (working prototype).