Inform

- Added is_mapping()

- Add end support to join().
- Allow previous logfile to be saved.
- Allow urgency to be specified on notifications.
- Allow render support in user-defined classes with addition of special methods.

- Added *error_status* argument to inform.Inform.
- Enhanced inform.plural. This enhancement is not backward compatible.
- Enhance for render() to allow it to be used in a __repr__ function.

- Added render_bar utility function.
- Added ProgressBar class.
- Added Info class.
- Added Inform.join_culprit method and join_culprit function.
- Allow culprit to be passed into Error.report() and Error.terminate() methods.
- Added Error.reraise method.
- Allow a codicil or codicils to be added to any informant.
- Added codicil named argument to informants and Error class.
- Added informant named argument to Error.
- Use colorscheme of active informer as default for colorizers.
- Error.get_culprit method now returns a tuple rather than a string.
- Added Error.join_culprit and Error.get_codicil methods.

- Added aaa() debug function.
- Added exit argument to done(), terminate(), and terminate_if_errors().
- terminate() now produces an exit status of 0 if there was no errors reported.
- Added set_culprit(), add_culprit() and get_culprit().

Tidied things up a bit.