Allows for more fine-grained configuration of what to ignore.

Introduce ServerIntrospector.getMetadata(Server).

fixes gh-419

This reverts commit 721fdc59.

* invalid_hostname:
  Added check for invalid hostname

The exception class has to be "fixed"

You may register a serviceId with invalid URI characters (e.g.: '_'), but the URI::getHost() fails when such chars are found.

* pull734:
  fixes gh-716 adds option to decode 404s

* pull663:
  Case insensitive Content-Encoding check

Fixes a problem with a header in the response containing
content-encoding in lowercase letters. Uses HttpHeaders for case
insensitve check.

Also fixes an issue checking if a request is made for gzip content.
If headers has more than gzip (ie gzip,deflate,sdch), checks if
contains gzip instead of equals to.

Fixes gh-662

* jkschneider-metrics-gauge-deconflict:
  Deconflict GaugeService provided by Servo/Spectator integration

Now uses spring-cloud-context NamedContextFactory.

see https://github.com/spring-cloud/spring-cloud-commons/issues/69

We need to use BeanFactoryUtils to search the context hierarchy
for custom instances.

Fixes gh-733

Add Servo metric poller and @EnableAtlas test

Update docs to indicate the need for spring-cloud-starter-atlas

Minor improvements to error messages for netflix.atlas.uri problems

* pull699:
  Add Zuul Proxy regex serviceId to route mapping

fixes gh-693

* gh-691:
  Enable configuration of the way HttpClient handles redirects