fixes gh-2318

Modfied RibbonCommandContext to make request entity resettable. fixes gh-892

* Remove @EnableDiscoveryClient and @EnableEurekaClient as there are now optional.  Fixes #2241.

Signed-off-by: Gregor Zurowski <gregor@zurowski.org>

Fixes gh-665

Fixes gh-1849

fixes #1741

fixes gh-1943

Signed-off-by: Gregor Zurowski <gregor@zurowski.org>

* add feign client properties

* configure feign builder from properties if exists

* change string config to class config and add unit test for feign client using configuration properties

* refactoring and add primary flag configuration

* add decode404 in feign client configuration properties

* change unit test properties decode404 to true

* remove lombok from FeignClientProperties and change primary attribute to default-to-properties

fixes gh-1931

* Support for re-writing Location Headers

* Added additional constructor for Route, removed auto-configuration of LocationRewriteFilter

* Polished docs, more tests

* Add options for RibbonCommand to use separate thread pools for hystrix

* Remove lombok annotation and Add getter/setter for ZuulProperties$HystrixThreadPool

* Add doc about how to configure hystrix thread pools in Zuul Developer Guide

* Add testcases for HystrixThreadPoolKey of RibbonCommand

* Tiny change about if block in AbstractRibbonCommand

this is now handled by spring-framework

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

Change /routes endpoint to use EndpointMvcAdapter and AbstractEndpoint.  

Fixes #1797

For more advanced filter examples.

fixes gh-1748

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

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-1073