[maven-release-plugin] copy for tag dnet-download-service-2.1.5
implemented layer file system for Object Store Service
fixed bug where the worker can't get next item from queue
loggg
fixed queue consumption
added further logs
changed level of debug
Changed plugin signature
added changes to BlackboardServerAction to go on failed arc if some exception happens
organized import removed warning
added property file
allow to disable ssl check. refactor.
formatted code
Implemented Report of download
Implemented URL redirection on DownloadWorker
Modified DownloadWorker to apply plugin inside the Thread
Implemented Update Size after the end of download
fixed problem on DummyPlugin
fixed case of wrong excpetion raised
updated download Item
fixed dependencies of download service