Upgrade Hystrix to 1.5.5

Updated SC Stream to Brooklyn SNAPSHOT

This fixes a case where the ribbon property is set `ribbon.IsSecure=false`, but because the eureka secure port was enabled, the uri created by ribbon was prefixed with https when it shouldn't have.

All places where isSecure is need have been consolidated into RibbonUtils.

fixes gh-1270

Previously with a `@FeignClient(name="http://bad_hostname")` would pass the start time test and fail later in runtime. The test now fails fast.

fixes gh-1257

This reverts commit 258e53a4.

Make Hystrix Thread Pool available while using Zuul 

Upgrade Feign to 9.3.0

Upgrade Feign to 9.2.0

fixes gh-1266

Conflicts:
	spring-cloud-netflix-core/src/test/java/org/springframework/cloud/netflix/ribbon/RibbonClientConfigurationTests.java

fix 'RibbonRequest' cannot to encode issues

Merge branch 'master' of https://github.com/spring-cloud/spring-cloud-netflix into zuul_hystrix_threadpool

This reverts commit 21df6e43.

A problem in Spring Boot means that the extra conditions are combined
with OR not AND, so it's a bug to have more than one until that
gets fixed (in an AnyNestedCondition).

See https://github.com/spring-projects/spring-boot/pull/6672

Merge branch 'context-path-prefix-support' of https://github.com/kakawait/spring-cloud-netflix into kakawait-context-path-prefix-support

- add zuul.add-host-header property to add Host header
- add port to X-Forwarded-Host as defined in RFC 7239
- extract PreDecorationFilter.filterOrder() into a public constant

fixes gh-1108

Add a check to current context as contentLength is already in the context
Get content length from Headers when RibbonCommandContext is built + add tests
Use request content length RibbonRoutingFilter
Add documentation for new zuul.ribbonIsolationStrategy property

fixes gh-339

What we're missing ATM is different documentation versions for different application versions. What this change does is that it's:

- finding out what is the current branch (e.g. 1.0.x)
- finding out out what is the name of the main adoc file (e.g. spring-cloud-sleuth)
- pulling the changes from gh-pages after checkout
- finding out what is the list of comma separated whitelisted branches (via the `docs.whitelisted.branches` prop)
- in gh-pages creating a folder with name of the branch  (e.g. /1.0.x)
copying all the docs/target/generated-docs/ to that folder
- if the branch from which we're calling the script is NOT master then we're changing the ${main.adoc}.html to index.html so that it's easier to access the docs (e.g. http://cloud.spring.io/spring-cloud-sleuth/1.0.x/)