#1341 SingleDeferredResult should uses RESULT_NONE from DeferredResult instead of having its own empty result.

fixes gh-1600

Make FeignClientRegistrar implement EnvironmentAware to inject the environment.  

Fixes gh-1568

Fix potential decoding and reencoding issues in query params when using SimpleHostRoutingFilter (#1464)

Some webserver are picky with the encoding (uWSGI for example) and the current code behavior of decoding and reencoding the query string can lead to valid requests
rejected by the backend after the modifications in Zuul. This commit adds an optional parameter to force the original encoding of the query string in SimpleHostRoutingFilter.

Fixes gh-971

This will clear up empty 200 responses.

fixes gh-1123

use `com.netflix.loadbalancer.DummyPing` instead of `NoopPing`

This eliminates the startup of another theadpool.

fixes gh-1504

Uses configuration from IConfigClient reference to always use the most up to date configuration.  Fixes #1481.

-additional refactoring from changes in s-c-commons

Fixes gh-1363

Instead of blocking them (which is the default behaviour of a
Spring MVC controller) Cors requests will flow through the Zuul
filters by default. Users can control it by grabbing the
ZuulHandlerMapping in a @PostConstruct and injecting some
CorsConfiguration via its setCorsConfigurations() method.

This fixes most of the issues people encounter when there are
multiple proxies in the request. The tricky thing is that there
is another header "Forwarded" that we don't recognize, but which
backends probably do, at least some of the time (since it is
from an actual RFC). The problem is that "Forwarded" does not
contain the ports, so Spring UriComponentsBuilder cannot use it
to rewrite links to a specific port. Since we do not support it
already, this change doesn't make things any worse, but the
corner case is there still.

Hystrix fallback support for Zuul routes.

Fixes gh-250.

fixes gh-1329

Secure ribbon urls were forced to use https scheme via UriComponentsBuilder, that was created from original uri. This transformation url encoded previously encoded url parts that were used to create builder. This was introduced in c883495f.

This change fixes double url encoding using RibbonUtils.updateToHttpsIfNeeded that fixes double escaping case and corner case with '+' in url as well.

Fixes gh-1382

Previously, parameter names with colons (ie foo:bar), caused an IllegalArgumentException because 41c36400 introduced UriTemplate to properly encode.

fixes gh-1193

Adds `@FeignClient.fallbackFactory` to define a `feign.hystrix.FallbackFactory`.

fixes gh-1117

* add config option to not ignore security headers
* fix field documentation of ignoreSecurityHeaders
* add documenation for  zuul.ignoreSecurityHeaders

fixes gh-1096

RibbonUtils now replace the encoded space character '+' in the query string in favor of the equivalent '%20' when rewriting the URI in https. This is due to UriComponentsBuilder verifying the allowed characters in the encoded URI when building to the URI java.net class. The '+' is considered illegal but is widely used in the field. (#1367)

Uses ribbon settings to set MaxConnTotal and MaxConnPerRoute. Also allows user to create a custom HttpClient as a constructor argument.

fixes gh-1149

This eliminates them being created for every zuul request.

Also makes properties consistent accross modules: ribbon.httpclient.*, ribbon.restclient.* and ribbon.okhttp.*

fixes gh-1150

* Check if object is already a ResponseEntity, if so return instead of wrapping in another ResponseEnitiy. Which caused headers and status code from original ResponseEnitiy to be lost and for body to be output with whole ResponseEntity instead of just the body

* added test

The apache http client and ok http client support delete with body, ribbon rest client does not.

fixes gh-949

fixes gh-1097