* Added util method to upgrade the connection to a secure one.

- Adds support for websocket URIs
- Fixes bug where a non-secure scheme other than http would be changed to https
- Deprecated `updateToHttpsIfNeeded` in favor of `updateToSecureConnectionIfNeeded`

* Expect http when no scheme was set

* Skip update to secure connection when the uri is empty

* Fixes double encoding when creating secure URLs.  Fixes #2478.

* Add support loadBalancerKey in RibbonRoutingFilter

* Add documentation about how to provide a loadBalancerKey to Ribbon

* Add integrationtest for RibbonRoutingFilter's loadBalancerKey support

* Adds backoff policies when retrying requests.  Fixes #2195

* fixing final variable

Lets user have full control over how the Observable is created with
sane defaults for eager/non-eager cases.

- The fix adds a necessary buffer between the rx-rs adapter and
the timeout operator introduced in AbstractCommand. Unfortunately,
the hystrix operator does not comply with RS backpressure requirements.
It will always request an unbounded demand to a source regardless of
the command consumer demand. With this commit we protect RS adapter and
downstream flow from overflow. Ideally a rework of the operator should
be planned.

* Add new Zuul filters endpoint and refactor routes endpoint
* Refactor FiltersEndpoint
- Extend from AbstractEndpoint and simplify code
- Move tests classes into package endpoint
- Remove usage of Lombok
* Conditionally enable Zuul routes and filters endpoints
* Provide FilterRegistry to FiltersEndpoint via constructor

Otherwise there would be an explosion of overloaded methods.

See https://github.com/spring-cloud/spring-cloud-commons/issues/265

fixes gh-2298

fixes gh-1982

* Move Archaius to its own module.  

Fixes gh-2300\

fixes gh-2317

fixes gh-2312

fixes gh-2314

fixes gh-2309i

These things are now much better dealt with in Spring MVC and WebFlux

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

According to:

https://docs.spring.io/spring/docs/current/javadoc-api/org/springframework/web/bind/annotation/RequestMapping.html#headers--

the `headers` field can take several formats:

1. Require the header with a concrete value: `"My-Header=myValue"`
2. Require the header with any value: `"My-Header"`
3. Require the header is absent: `"!My-Header"`
4. Require the header with a negated value : `"My-Header!=myValue"`

This fixes `parseHeaders` for cases 2-4 (which previously threw a `StringIndexOutOfBoundsException`).

Fixes gh-1778.