Deriving from Spring Clouds ProxyRouteLocator has become too difficult. It would
have required to either set fixed ZuulProperties or providing a DiscoveryClient.
So we are shipping our own lean version of it. Since the PreDecorationFilter is tightly
coupled to the ProxyRouteLocator we also have to use our own stripped down version.

closes #123

remove logfileEndpoint
rename logback.xml to logback-spring.xml in samples

fixes #98

To enable, you just have to add a DiscoveryClient to your Spring Boot Admin Server.
Also did some code polish.
Closes #44