Tidbits

Bugfixes
- avoid potential log duplication when not explicitly using the null logger
- this should also fix edge case logging weirdness when using non-null loggers in some Python 3.6 multiprocessing environments

Meta
- distribute license in PyPI package
- include changelog link in PyPI

Fixes
- fix edge-case-ey breakages in `JsonFormatter.__init__()` on Python 2.7

Convenience
- you can now install the `gcloud` and `sentry` extras rather than needing to handle optional sub-dependencies manually

Compatibility
- verified support with Python 3.7

Internal
- avoid manually handling SENTRY_DSN
- a bunch of repo cleanups

- chore(meta): include MIT license

- fix(ci): drop python 3.3 support
- fix(ci): fix pylint bug
- fix(log): fix bad set_loglevel logic

BREAKING:
- rename `set_handler` to `set_handler_globally`
- create `set_handler` for only individual loggers
- allow `set_handler_globally` to ignore some loggers

- feat(log): allow passing logger names to all utilities