Add the ability for ribbon clients to specify response status codes they would like to retry.  Fixes #1540.

fixes gh-1786

This reverts commit a628ba1b.

GH-1334: Support for eagerly initializing zuul Ribbon contexts

By default, `LoadBalancerBuilder` built a load-balancer with a `PollingServerListUpdater`. This change introduces a `ServerListUpdater` bean which creates a `PollingServerListUpdater(IClientConfig)` so that `ribbon.ServerListRefreshInterval` is respected.

 fixes gh-1304

Update docs as @Autowired fails with many beans

Fix a suspected typo. @Autowired throws a `NoUniqueBeanDefinitionException` if there are multiple beans of the same type without a primary, but the documentation said multiple beans 'cause `@Autowired` to work', rather than 'not work'.

fixes gh-1766

 Previously, when feign used the Ribbon RestClient, an exception was thrown if Content-Length was set. Over time, feign has moved away from RestClient, yet removing the header still happened.

 Fixes gh-1705

Also add com.squareup.okhttp3:logging-interceptor dependency management.

fixes gh-1752

`MetricsRestTemplateConfiguration` creates a BeanPostProcessor used to configure RestTemplate instances when added to the application context. It should be made @ConditionalOnClass(RestTemplate) instead of @ConditionalOnBean(RestTemplate) since it should be present *before* any RestTemplate bean instance is created. (#1747)

fixes gh-1153

fixes gh-1745

Disable Hystrix support when using Feign by default

fixes gh-1073

prefer-ip-address does not work in statusPageUrlPath when management port != server port

This change gets `prefer-ip-address` via a relaxed property resolver to set the value during the creation of the `EurekaInstanceConfigBean`.

fixes gh-1724

If DiscoveryClient.getLocalServiceInstance() throws an exception (ie consul isn't available), log a warning and continue. This is useful for dev type environments.

fixes gh-1603

Eureka ServerConfiguration is now auto-configuration based, instead of being explicitly specified via configuration pulled in through @EnableEurekaServer. This way specific beans can be conditionally overridden, configuration can be re-ordered.
Supports PeerEurekaNodes bean to be overridden by the user

Fixes gh-1717

Refactor ZoneUtils class

fixes gh-1731

Remove duplicate null check

Fixed typo