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

In case dropwizard is used the heap metrics are in bytes and not in kilobytes.
This is deteceted by the presence of heap.max. For Spring Boot 2.0 there is an
issue filed to deliver bytes see spring-projects/spring-boot#6413

fixes #234

Since a HEAD request to the heapdump triggers a dump we need to test the
availability of the heapdump endppoint via OPTIONS-request.
To get this working we need to ensure that the OPTIONS-request are dispatched
to the zuul servlet as this wasn't done prio to this commit adding the
OptionsDispatchingZuulController.

Update quick start doc link to 1.3.4

With this commit you can from now on register the application on multiple
servers. You need to set spring.boot.admin.register-once to false and
assign a list of urls to spring.boot.admin.url

fixes #230

Detecect endpoints by making a HEAD request instead of querying the configprops
since it is broken when having a second applicationContext

fixes #226