Move Spring dependencies to dependencyManagement section of parent pom. Soon we will have 2 modules that depend on Spring.
Bugfix. TimeUnit was seconds but value was set to 5000, should be 5.
Add @PreDestroy annotation on close method of ZipkinSpanCollector.

If you use Spring this will be picked up by Spring and make sure the
SpanCollector is properly closed when ApplicationContext gets shut down.
Update documentation and status of 2.0-SNAPSHOT.
Add brave-impl-spring module.

Spring dependency injection configuration classes