Add informational step 'note that...' from behave4cmd (jenisys).
Add repr operator to make Matcher objects more readable in Debugger.
Formatters are now created only once (was: once for each feature).
JSON formatter can now generate valid JSON output.
Add utility scripts:
  * behave.step_durations.py: Shows longest step durations based on JSON data.
  * json.format.py: Reformats JSON files (and validates well-formedness).
Table: Add helper functions to simplify exploratory testing w/ tables (and table annotations) and step processing with tables.