Gh 586 loadbalancer starter (#599)

* Add loadbalancer starter. Add property to set BlockingLoadBalancerClient
as default non-reactive loadbalancer. Start working on auto-enabling caching.

* Automatically enable caching. Fixes gh-585.

* Add tests.

* Add reference docs.

* Change property name.

spring-cloud-starter-loadbalancer/pom.xml

@@ -0,0 +1,39 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+		 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+		 xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+	<parent>
+		<groupId>org.springframework.cloud</groupId>
+		<artifactId>spring-cloud-commons-parent</artifactId>
+		<version>2.2.0.BUILD-SNAPSHOT</version>
+		<relativePath>..</relativePath>
+	</parent>
+	<modelVersion>4.0.0</modelVersion>
+
+	<artifactId>spring-cloud-starter-loadbalancer</artifactId>
+	<name>spring-cloud-starter-loadbalancer</name>
+	<description>Spring Cloud Starter LoadBalancer</description>
+	<url>https://projects.spring.io/spring-cloud</url>
+	<organization>
+		<name>Pivotal Software, Inc.</name>
+		<url>https://www.spring.io</url>
+	</organization>
+	<properties>
+		<main.basedir>${basedir}/../..</main.basedir>
+	</properties>
+
+	<dependencies>
+		<dependency>
+			<groupId>org.springframework.cloud</groupId>
+			<artifactId>spring-cloud-starter</artifactId>
+		</dependency>
+		<dependency>
+			<groupId>org.springframework.cloud</groupId>
+			<artifactId>spring-cloud-loadbalancer</artifactId>
+		</dependency>
+		<dependency>
+			<groupId>org.springframework.boot</groupId>
+			<artifactId>spring-boot-starter-cache</artifactId>
+		</dependency>
+	</dependencies>
+</project>

spring-cloud-starter-loadbalancer/src/main/resources/META-INF/spring.provides

@@ -0,0 +1 @@
+provides: spring-cloud-loadbalancer