fixes gh-236

If you are using AMQP there needs to be a ConnectionFactory (from
Spring Rabbit) in the application context. If there is a single
ConnectionFactory it will be used, or if there is a one qualified as
@[Hystrix,Turbine]ConnectionFactory it will be preferred over others,
otherwise the @Primary one will be used. If there are multiple
unqualified connection factories there will be an error.

See https://github.com/spring-cloud/spring-cloud-bus/issues/13

It didn't depend on Ribbon at all so it can live in the commons
project.

Listen for heartbeats from discovery so that state changes can trigger
a new status (and the client doesn't rely on the old address of the
server if it has now changed).

Fixes gh-232

fixes gh-225

It doesn't make sense to @EnableFeignClients in autoconfig
because the user needs to specify a package to scan. It does
make sense (sort of) to set up the encoder/decoder/logger etc.

See gh-226

When the URL is passed down to Ribbon and reconstructed from
a LoadBalancer the Server only knows about host and port, so the scheme
has to come from the original declaration.

There's still a potential problem with Eureka remote services that
are available with a non-secure port as well (probably fairly rare).

Fixes gh-221

Users need to know how to configure and use the Eureka
metadata because it isn't immediately obvious and does
require some decisions to be made.

Fixes gh-102

fixes spring-cloud/spring-cloud-bus/issues/7

fixes gh-201

fixes 208

fixes gh-210

To write file data the message converter needs the file content
to be provided in the form of an HttpEntity per file.

Fixes gh-197 again

fixes gh-204

only update route location if location is empty.  Fixes bug introduced in 18b346de

update the serviceId and location for statically configured routes that are also part of serviceDiscovery.

fixes gh-199

If the ServerProperties contain a servletPath then the handler mapping
does not contain that prefix, but the incoming request URI does. This leads
to some interesting prefix stripping gymnastics. All the existing tests
assumed that the prefix was empty (the default for a Spring boot app).

See gh-199

This reverts commit 29bee28d.

and also allow explicitly configured services to be unignored. I.e.

zuul:
  ignoredServices: *
  routes:
    foo: /foo/**

Will expose only the foo service.

Fixes gh-198

Instead of building a String, if we use an existing
HttpMessageConverter from Spring web, we can support multipart
form data.

Fixes gh-197 (hopefully)

Now that blitz4j 1.36.0 is out, with a bit of hackery we can prevent
it from barfing on startup. Seems worth it (and certainly makes
it easier to embed Eureka server).

Fixes gh-3

The Eureka instance has to provide status page and health check
URLs. We only provide a sensible default if the app is a vanilla
Actuator. This change shows users explicitly how to customize those
settings.

Fixes gh-192

Fixes gh-194

The ProxyRouteLocator now has a retryable property (default
null which means Ribbon will choose the default - usually false).

Fixes gh-115, fixes gh-124

When running from /hystrix or from / (with a forward) the
webjars and the monitor endpoint need to be resolvable, so
we need to use the FTL macros again.

Fixes gh-193