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.

pom.xml

@@ -155,6 +155,7 @@
 		<module>spring-cloud-commons</module>
 		<module>spring-cloud-loadbalancer</module>
 		<module>spring-cloud-starter</module>
+		<module>spring-cloud-starter-loadbalancer</module>
 		<module>docs</module>
 	</modules>
 </project>