also fix table styling in httptraces, auditevents and sessions

In order to do a relaease not waiting for Spring Cloud
Finchley.REALEASE move all depedent stuff into a seperate module which
can be excluded during build

fixes #728

This makes sure that the headers are written to the output stream
before the async dispatch. Otherwise we end up with strange NPEs
when flushing the buffer on writing the body.

fixes #715

..to gain more performance and reduce gc pressure

fixes #713

closes #713

closes #697

The system.load.average.1m metric is not available on all platforms.
Therefore we ignore errors from fetching it.

closes #697

Fixes stalls in threaddump view due to not completing responses - only
reactive applications were affected so far.

The TaskScheduler used for periodically registering is removed from the
application context and moved to the ApplicationRegistrationListener.

see #478