Ontospy

- Extract individuals (instances) from a graph on-demand
- Option `-i` from command line
- Option `hide_individuals=False` from `Ontospy` class
- All gendocs visualizations updated so to handle instances
- Improve handling of multi-ontology graphs: ontologies ordered alphabetically by default
- Add `format` parameter to `scan` command
- Fix for `--verbose` option which was broken in CLI

* refactored all 'printing' operations
* `printDebug` => stderr
* `printInfo` => stdout
* remove all direct calls to `click.secho`
* remove all 'print' statements

* updated sigma.js visualization features

* add `pref_title` and `pref_language` options to ontospy
* update CLI to accept these parameters for documentation generation
* eg `ontospy gendocs -l --preflabel label`
* improve all viz templates to use user provided titles
* add `|linebreaks` to bestDescription method for better rendering
* various code improvements for tests

- `gendocs` option: `no browser` prevents opening html viz in browser
- `gendocs -l` added as shortcut of `--lib`