With this change the AbstractNotifier isn't specialized on status changes, but
the default behaviour for the existing notifiers isn't changed.
In addition the existing notifiers have been improved so that subclassing has
become easier.
To have existing notifiers acting on other events you need to override
shouldNotify().

fixes #270

fixes #269

closes #237

fixes #263

When includeing spring-cloud-netflix-hystrix-amqp to your application it looks
like that the ApplicationReadyEvent is fired twice (from main and child
application context). So we need to take care that only the events from the
main applications are taken into account.

fixes #260

Using an absolut url in $http.get doesn't work when the server.context-path has
been changed for the admin server. Like in all other places a relative url has
to be used.

fixes #256

Remove the activiti endpoint from the default set of proxified endpoints.
This aligns with the non present defaults for hystrix.

By using the netflix/hystrix-dashboard this module allows you to view the
metrics from hystrix/turbine in the spring boot admin server. This module needs
to be added explicitly.

closes #147

As now with spring boot 1.4 there is a special goal for generating the build-
information, we use it for displaying the version in spring boot admin. The old
info.version property still works but is deprecated. From now on
build.info.version is taken into account.

Unfortunately js-yaml currently renders all strings in singlequotes, these are
included by linkifyjs in the href. So this commits adds a formatHref option to
remove these dangling singlequote.

As it turns out (rather obvious) that the ThreadPools for registration and
status updating needs to be destroyed on application shutdown so that the
worker threads gets cancelled. To achieve this we simply register the
ThreadPools as spring beans (since they are implementing DisposableBean).

fixes #253

Apparently when the Netty4ClientHttpRequestFactory is being used the content-
lenght header is not being set in the POST request. Therefore the simple one is
now being hardcoded to override decetion by the RestTemplateBuilder.

fixes #248

Fix the usage of RestTemplateBuilders which wasn't covered by PR #247

The RestTamplateBuilder doesn't save the arguments, it returns a new Builder instance, with the saved arguments. So you have to save the builder everytime you call a function on it.

The 1.4.0 release was a total disaster. Webpack didn't build the css correctly
because of travis using an ancient nodejs version.

fixes #243

When having registered some applications via discovery and some via http you
can now add the appication names of the non-discovery to the ignored services
so that they won't considered as stale an be removed from the registry by the
ApplicationDiscoveryListener.

fixes #244

With this commit you can specify the management.port for a discovered service
via the metadatamap.

After this commit the applications in the overview are grouped by application-
name. In case the search box is used all groups get expanded automatically.
Additionally the info column is now expandable via button and not a pre-section
anymore.

closes #218