Add `verbose` kwarg

[lgbouma]

Discussed in: https://github.com/hippke/tls/issues/96

• [x] The code builds clean without any errors or warnings
• [x] Existing test cases work correctly
• [ ] New test cases have been added to cover the additional and/or changed functionality

Note: I haven't added any new tests, because it's just adding one kwarg to manage print output. @hippke , please let me know if you'd like the tests regardless and I can cook something up. The default test cases run with the output as normal (i.e. the default functionality is unchanged).

[hippke]

Hey, thank you so much, very good PR! Can you fix the typo in transit.py where "verbose" is "verobse"?

[lgbouma]

Thanks, and that was done in 9b5728d !