Chaostoolkit-opentracing

Changed

- Moved to OpenTracing 2 API
- [BREAKING CHANGE] this control does not expose spans as explicit properties
of the tracer any longer. This was due to a limitation of some of the
Open Tracing clients (namely Jaeger). Now these clients have been updated
to the newer version, this is not needed anymore. You can use the
active span of the tracer as expected. This only breaks if you accessed
directly those properties.

Added

- Marked with `error:true` deviated hypotheses and failed activities

Added

- More configuration to the Jaeger client (to talk to Zipkin)

Changed

- Open Tracing control as per the Chaos Toolkit [specification][spec]

[spec]: https://docs.chaostoolkit.org/reference/api/experiment/#controls

Added

- Initial release