Expose security context to any Hystrix command.

* pull1242:
  Add @Qualifier customization for @FeignClient

Changed test to use @Qualifier.
Add documentation to reference the new attribute.

fixes gh-1240

* pull1244:
  Fixed double-encoding issue in RibbonClientConfiguration

fixes gh-1241

fixes gh-1157

Conflicts:
	spring-cloud-netflix-core/src/main/java/org/springframework/cloud/netflix/zuul/filters/route/support/AbstractRibbonCommand.java

Content-length not properly set when using the FormBodyWrapperFilter

Fix issue gh-1054

Conflicts:
	spring-cloud-netflix-core/src/test/java/org/springframework/cloud/netflix/zuul/filters/route/okhttp/OkHttpRibbonCommandIntegrationTests.java

FormBodyWrapperFilter may add multiples of every multipart part to a request

Migrate tests to Spring Boot Test 1.4

Fix an issue where the FormBodyWrapperFilter would encode the form parameters differently than on the original request.

The FormBodyWrapperFilter handles the application/x-www-form-urlencoded. In the case of requests received by curl or javascript, the FormHttpMessageConverter will reencode the parameters differently (for example, '(' will be encoded while it's not with the javascript encodeURIComponent method).

While this doesn't create any problem, the content length was not properly set in AbstractRibbonCommand. This causes the form params being stripped or the backend server would wait a long time for additional bytes depending on if the content length header was bigger/smaller than the actual data.

Changed version and group id to use latest OpenFeign release

Fixes gh-1214

Fixed an issue where the pre FormBodyWrapperFilter adds multiples of every multipart part to a request