[maven-release-plugin] copy for tag 0.20.9 

[maven-release-plugin] copy for tag 0.20.8 

MockSpan throw ex when setting data after finish (opentracing#98) 

Allow consumers to define tags (opentracing#96) I think we all agree to merge this.

[maven-release-plugin] copy for tag 0.20.7 

[maven-release-plugin] copy for tag 0.20.6 

Enable license plugin in pom.xml (opentracing#78) 

Make the Travis build care less about pom.xml 

Allow to override MockTracer (opentracing#77) 

[maven-release-plugin] copy for tag 0.20.4