Documents intent of client tests

Fixed version log

JAXRS: Fix NPE when @path is first on a method

Apache HTTP client hates to have the Content-Length set

It always sets the header itself and if we set it as well it barfs
so it is better just to avoid setting it at all.

support PUT with empty body parameter

follow-up commit to OpenFeign#271

Allows HystrixFeign.Builder to be used incrementally

Uses covariant overrides so that those collecting Feign configuration
via `Feign.Builder` can cast into `HystrixFeign.builder` to target an
api.

Closes OpenFeign#313

Fixes CHANGELOG

Document and expose HystrixDelegatingContract

HystrixDelegatingContract is reusable when developers like @marcingrzejszczak make custom invocation handlers.

Merge pull request OpenFeign#303 from Netflix/bumps

Bumps dependency versions, most notably Gson 2.5 and OkHttp 2.7

SynchronousMethodHandler does not wrap exceptions thrown by Decoder#d…

…ecode in decode404 mode

Removing exception wrapping adds flexibility to the interplay of Decoder and ErrorDecoder:
A Decoder can now delegate to an ErrorDecoder and the original ErrorDecoder exception gets
thrown rather than a Feign-specific DecodeException. An example use-case is a Jackson/Gson
implementation of special 404-handling of Optional<Foo> methods: when the Feign client has
decode404() enabled, then the Decoder is in charge of dispatching 404 to Optional#absent
where applicable, or to a delegate ErrorDecoder otherwise; consistent exception handling
requires that the exception produced by the ErrorDecoder does not wrapped.