Sleuth now uses Brave (#829)

with this pull request we have rewritten the whole Sleuth internals to use Brave. That way we can leverage all the functionalities & instrumentations that Brave already has (https://github.com/openzipkin/brave/tree/master/instrumentation).

Migration guide is available here: https://github.com/spring-cloud/spring-cloud-sleuth/wiki/Spring-Cloud-Sleuth-2.0-Migration-Guide

fixes #711 - Brave instrumentation
fixes #92 - we move to Brave's Sampler
fixes #143 - Brave is capable of passing context
fixes #255 - we've moved away from Zipkin Stream server
fixes #305 - Brave has GRPC instrumentation (https://github.com/openzipkin/brave/tree/master/instrumentation/grpc)
fixes #459 - Brave (openzipkin/brave#510) & Zipkin (openzipkin/zipkin#1754) will deal with the AWS XRay instrumentation
fixes #577 - Messaging instrumentation has been rewritten

spring-cloud-sleuth-samples/spring-cloud-sleuth-sample-feign/src/main/java/sample/SampleController.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2013-2015 the original author or authors.
+ * Copyright 2013-2018 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.

spring-cloud-sleuth-samples/spring-cloud-sleuth-sample-feign/src/main/java/sample/SampleFeignApplication.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2013-2015 the original author or authors.
+ * Copyright 2013-2018 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.