[#106] Converted UUID to Long

- Changed Random instantiation to a shared Random
- Changed the name of the converter
- Changed generator into random
- Span id is now non-nullable.
    - it gets generated in the http filter if it's not there
    - it's generated in the spring-integration channels if it wasn't set

spring-cloud-sleuth-stream/src/main/java/org/springframework/cloud/sleuth/stream/ServerPropertiesHostLocator.java

@@ -80,8 +80,8 @@ public class ServerPropertiesHostLocator implements HostLocator {
 
 	private String getServiceName(Span span) {
 		String serviceName;
-		if (span.getProcessId() != null) { // TODO: javadocs say this isn't nullable!
-			serviceName = span.getProcessId().toLowerCase();
+		if (span.getProcessId() != null) {
+			serviceName = span.getProcessId();
 		}
 		else {
 			serviceName = this.appName;

spring-cloud-sleuth-stream/src/test/java/org/springframework/cloud/sleuth/stream/ServerPropertiesHostLocatorTests.java

@@ -16,17 +16,18 @@
 
 package org.springframework.cloud.sleuth.stream;
 
-import java.net.InetAddress;
-import java.net.UnknownHostException;
-import java.util.Collections;
 import org.junit.Test;
 import org.springframework.boot.autoconfigure.web.ServerProperties;
 import org.springframework.cloud.sleuth.MilliSpan;
 
+import java.net.InetAddress;
+import java.net.UnknownHostException;
+import java.util.Collections;
+
 import static org.assertj.core.api.Assertions.assertThat;
 
 public class ServerPropertiesHostLocatorTests {
-  MilliSpan span = new MilliSpan(1, 3, "name", "traceId", Collections.<String>emptyList(), "spanId", true, true, "processId");
+  MilliSpan span = new MilliSpan(1, 3, "name", 1L, Collections.<Long>emptyList(), 2L, true, true, "process");
 
   @Test
   public void portDefaultsTo8080() {

spring-cloud-sleuth-stream/src/test/java/org/springframework/cloud/sleuth/stream/StreamSpanListenerTests.java

@@ -85,7 +85,7 @@ public class StreamSpanListenerTests {
 
 	@Test
 	public void rpcAnnotations() {
-		Span parent = MilliSpan.builder().traceId("xxxx").name("parent").remote(true)
+		Span parent = MilliSpan.builder().traceId(1L).name("parent").remote(true)
 				.build();
 		Trace context = this.traceManager.startSpan("child", parent);
 		this.application.publishEvent(new ClientSentEvent(this, context.getSpan()));