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

Helps with the confusion seen in #1365

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)

Moved common functionality to AbstractLoadBalancingClient

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

This reverts commit 088afa6d.

Fixes XXE vulnerability in Eureka Server (external entity processing
on by default in older versions of the library).

The SimpleHostRoutingFilter now accepts normal -Dhttps.proxy= and
-Dhttps.port= settings (and other things that generally work with
java.net).

Fixes gh-510

* improve-formbodywrapperfilter-test:
  Add test on FormBodyWrapperFilter to avoid regressions (#1171)

Allow override of /hystrix.stream location via management.port metadata.

Use statusPage/healthCheckUrlPath w/ custom management.port

Added RelaxedPropertyResolver to handle multiple valid formats for
eureka properties.  Added tests.

Fixes gh-1348

* 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

Rather than hard code the default maxSemaphores for zuul use the already defined `zuul.semaphore.maxSemaphores` property.

fixes gh-1332

Fix lastFetch status calculation.

Was previously milliseconds/seconds when calculating whether to display the message about reporting failures.

fixes gh-126

This reverts commit 3c1a23e7.

fixes gh-1319

Remove dep on commons-lang in DimensionalServoMetricNaming (#1268)