* Implement OT 2.0 support. (#31)
* Add tag & log.
* Report code coverage as part of testing.
* Add a public accessor to the underlying Tracer.
* Add linting check.
* Remove the lock for setting the global tracer. (#35)
* Move DjangoTracer and related elements to DjangoTracing.
* Default to tracing all when using the middleware.
* Add a start span hook.
* Update our README with our latest changes.
* Enable Django 2 support.