removed classes now in spring-cloud-commons

If the prefix is set we also set configPath=<prefix> in the
instance metadata, so config clients can pick it up and add it
to the home page URL.

Fixes gh-64, fixes gh-65

See gh-42

Add support for Ribbon loadbalancing in RestTemplate via an HttpRequestInterceptor that when supplied a uri such as http://myservice/my/endpoint (where myservice is a service as defined in a service registry, such as Eureka), it replaces 'myservice' with the actual host and port as returned from the configured ribbon loadbalancer.

closes gh-12

Without extracting to autoconfig the @ConditionalOnMissingBean won't
always work because it is dependent on the order of the configuration
classes being processed (and autoconfig always somes last).