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- Add support for indicating if a global tracer has been registered (109) <Mike Goldsmith>
- Use pytest-cov==2.6.0 as 2.6.1 depends on pytest>=3.6.0 (113) <Carlos Alberto Cortez>
- Better error handling in context managers for Span/Scope. (101) <Carlos Alberto Cortez>
- Add log fields constants to opentracing.logs. (99) <Carlos Alberto Cortez>
- Move opentracing.ext.tags to opentracing.tags. (103) <Carlos Alberto Cortez>
- Add SERVICE tag (100) <Carlos Alberto Cortez>
- Fix unclosed active scope in tests (97) <Michał Szymański>
- Initial implementation of a global Tracer. (95) <Carlos Alberto Cortez>