GDA-5558 when doing a panic stop, first find any command queues and
abort them.
Updated the test files for NexusDetectorWritingTest and
testDataWriterExtender (in ScanToNexusTest) so that they contain the
correct NXMetaDataProvider sub-tree.
Merge branch 'master' of
ssh://dascgitolite@dasc-git.diamond.ac.uk/gda/gda-core.git
Merge branch '8.30'