use `com.netflix.loadbalancer.DummyPing` instead of `NoopPing`

This eliminates the startup of another theadpool.

fixes gh-1504

Fix issue gh-1054

Allows ribbon class name properties to be used to define beans.

This seems like boilerplate, but works, though not easily extensible.

fixes gh-927

fixes gh-1091
closes gh-958

When using property placeholders in the @RequestMapping annotation the ones placed in the headers attribute do not get replaced. This appears to be because the other attributes, such as the url, use the resolve() function to perform the substitution whereas the header is parsed as-is. This change adds a call to resolve for each side of the equals in the header string so that the properties are substituted correctly.

Fixes gh-894

Includes name and url attributes.

fixes gh-414

It turns out that the suckiness of Zuul with multipart requests
comes almost entirely from the Multipart handling in Spring's
DispatcherServlet. This change makes the proxy routes available
on an alternative path /zuul/<normal_path> (where
/zuul is the default value of zuul.servletPath). I have
tested those with 800MB file uploads using the main method in
the FormZuulServletProxyApplicationTests and the main
observation is that there is no OutOfMemory error (no-one tries
to download the complete request body). It works with Ribbon
and with the simple (HttpClient) filter. With Ribbon you
will need to set some timeouts if you want to upload files
as large as that, e.g. see application.yml in the tests:

hystrix.command.default.execution.isolation.thread.timeoutInMilliseconds: 60000
ribbon:
  ConnectTimeout: 3000
  ReadTimeout: 60000

You need to set "Transfer-Encoding: chunked" in the
incoming request. Chrome does not do this by default
apparently, but I was able to test with curl, e.g.

$ curl -v -H "Transfer-Encoding: chunked" \
  -F "file=@mylarg.iso" \
  localhost:9999/zuul/direct/file

The old proxy paths through the DispatcherServlet are still
available (for backwards compatibility and for convenience of
having the paths available at the root of the context path).

Fixes gh-254

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

The Zuul filter registry has to be cleareed (including a cache in
a private field in FilterLoader, yuck).

Ribbon and simple host reverse proxy now share quite a lot of
code (everything to do with headers).

Fixes gh-103

User can now specify zuul.routes.*.{path,url,serviceId} (with
"url" and "serviceId" mutually exclusive (and "location" is a
synonym) separately, or can use a one-one short form, like the
old style.

See gh-77

zuul.route -> zuul.routes
zuul.mapping -> zuul.prefix

Bean instantiation ordering was causing external (user-supplied)
filter beans to replace the defaults, not append to them. Separating
out the autowired map of beans into a spearate class was enough to
fix it.

Fixes gh-78

E.g.

zuul:
  route:
    testclient: /testing123/**         # service mapping
    http://localhost:8081: /stores/**  # physical mapping

This allows mappings to be at the root and not have to be prefixed.  It also allows mappings to fall through to other handler mappings.  Patterns are now Ant-style via AntPathMatcher.

fixes gh-72

fixes gh-40

Removed old zuul module.

fixes gh-14