Add ribbon/zuul features and docs plus a sample

spring-cloud-sleuth-samples/spring-cloud-sleuth-sample-zipkin/src/main/java/sample/SampleBackground.java

@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-package org.springframework.cloud.sleuth.sample;
+package sample;
 
 import java.util.Random;
 

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

@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-package org.springframework.cloud.sleuth.sample;
+package sample;
 
 import java.util.Random;
 import java.util.concurrent.Callable;

spring-cloud-sleuth-samples/spring-cloud-sleuth-sample-zipkin/src/main/java/sample/SampleZipkinApplication.java

@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-package org.springframework.cloud.sleuth.sample;
+package sample;
 
 import org.springframework.boot.SpringApplication;
 import org.springframework.boot.autoconfigure.SpringBootApplication;
@@ -49,7 +49,7 @@ public class SampleZipkinApplication {
 
 	// Use this for debugging (or if there is no Zipkin collector running on port 9410)
 	@Bean
-	@ConditionalOnProperty("span.logging.enabled")
+	@ConditionalOnProperty(value="sample.zipkin.enabled", havingValue="false")
 	public SpanCollector spanCollector() {
 		return new LoggingSpanCollectorImpl();
 	}

spring-cloud-sleuth-samples/spring-cloud-sleuth-sample-zipkin/src/main/resources/application.yml

@@ -9,9 +9,9 @@ logging:
   pattern:
     console: '%clr(%d{yyyy-MM-dd HH:mm:ss.SSS}){faint} %clr(%5p) %clr(${PID:- }){magenta} %clr(---){faint} %clr([trace=%X{X-Trace-Id:-},span=%X{X-Span-Id:-}]){yellow} %clr([%15.15t]){faint} %clr(%-40.40logger{39}){cyan} %clr(:){faint} %m%n%wex'
 
-span:
-  logging:
-#    enabled: true
+sample:
+  zipkin:
+#    enabled: false
 
 endpoints:
   health: