Merge pull request #1375 from mmeisinger/REL2.0

OOIION-1343: Extension to import_dataset tool to stop data agents / REL2.0
Change assert to PlatformException to enable debug of ooiion-1327
fix exception check
Merge pull request #1376 from MauriceManning/1327_rebase2

ooiion-1327 Fix validation check in _instruments_shutdown_and_terminate
OOIION-1342. Remove two unused computed attributes