Use StringBuffer for String concatenation

Format indent adjustment

* Add support loadBalancerKey in RibbonRoutingFilter

* Add documentation about how to provide a loadBalancerKey to Ribbon

* Add integrationtest for RibbonRoutingFilter's loadBalancerKey support

* Adds backoff policies when retrying requests.  Fixes #2195

* fixing final variable

Incorrect statusPageUrl and healthCheckUrl are reported to Eureka if management.context-path is not set (#2145)

Follows: https://github.com/spring-cloud/spring-cloud-netflix/pull/1317

Probably we could import a bom from feign.