Fix Feign Compression Config Order

Currently all errors during writing to the outputStream are ignored. So the
response is read to the end. This is a problem when the response is
infite or very long running (`hystrix.stream` for example) and results in the
socket never being closed and eating up threads (on zuul and the proxied
backend). With this commit the errors during writing are not ignored resulting
in closing the response.

fixes gh-1824

This reverts commit 5d9363b3.

Adds conditional on Ribbon class to RibbonAutoConfiguration

 Previously, when feign used the Ribbon RestClient, an exception was thrown if Content-Length was set. Over time, feign has moved away from RestClient, yet removing the header still happened.

 Fixes gh-1705

(cherry picked from commit 15e01dfe)

Makes Spring Retry optional for Zuul

Add Retry Logic To Zuul Using Spring Retry.  Fixes #1295

Fixes gh-1663

fixes gh-1616

A new version of httpclient introduced by boot changed the behaviour that previously allowed the charset. It now has to be parsed out and passed to the apache `ContentType` object explicitly.

fixes gh-1649

Set the default buffer size to 8192 to match Tomcat and Jetty defaults
Use a buffer per worker thread and use it for subsequent requests