fixed rebase issues.
added torrent feature toggle.

dropped NzbClub.
FreeSpaceSpec will return true is free space check returns null
Adding some trace logging when setting last execution time for tasks
Merge branch 'torrent' into develop
fixed broken tests.
cleanup CommandId from MappedDiagnosticsContext
split MessageAggregator in EventAggregator and CommandExecutor
missed files.
reject all updates if in linux.
added global NzbDrone namespace.
stop trying to load place holder image for placeholder when server is offline.
added sample check for remote episode.
added test for InheritFolderPermissions
don't log signalr heartbeat exceptions as EPIC FAIL.
added test for command executed event
less chatty command events.
stop NzbDrone.Common.Tests from killing the runner.
guard against InheritFolderPermissionsNotImplementedException in linux.
added folder logging to isproduction test. better process name detection in mono.