do not close underlying UDP bootstrap in case of processor exceptions. fixes #426
use SAFE mongodb write concern
bump to rc.3
REST API for cached realtime alert checks of streams. /cc @dennisoelkers
do not respect grace time in manual alert check
Adding first steps of DI to replace omnipresent Core object someday

Still WIP, currently the MetricRegistry and MongoConnection is injected,
      more to come.