BLXVI-117 (8.38) Fixed regression with ScanDataProcessorResult
(8.38) Added getMeta method to metadata.py that gets metadata from the relevant source.
(8.38) Added setFilePrefix method to IncrementalFile to match the functionality offered by NexusDataWriter's SRS file functionality.
(8.38) - Changed NexusDataWriter to no longer require description/type/id strings.
(8.38) Removed unsupported method from NexusDataWriter (nobody was using it).
(8.38) Added debug message to log if NexusDataWriter.makeMetadataScannableFallback fails when creating group (previously it was silently ignored).
BLXVI-134 (8.38) - workaround for the fact that
AbstractContinousScanLine sets HardwareTriggering to false before
atScanEnd is called
Merge branch '8.38.mt' into 8.38
Fixed TestScanDataProcessorResult to account for c107ad1f

See BLXVI-117 - commit c107ad1f (cherrpicked to 252c90b6).
TestScanDataPrcessorResult was not updated to account for changes made
to ScanDataProcessorResult.
add option to provide detector pixel size units in NXDetector node which is required by 2D diffraction data reduction project.
Merge branch '8.38' of ssh://dascgitolite@dasc-git.diamond.ac.uk/gda/gda-core.git into 8.38

Conflicts:
	uk.ac.gda.core/src/gda/device/detector/nxdata/NXDetectorDataFileLinkAppender.java
Merge remote-tracking branch 'origin/8.38' into gda-8.42

Conflicts:
	uk.ac.gda.core/src/gda/data/scan/datawriter/NexusDataWriter.java
add option to provide detector pixel size units in NXDetector node which is required by 2D diffraction data reduction project.

Conflicts:
	uk.ac.gda.core/src/gda/device/detector/nxdata/NXDetectorDataFileLinkAppender.java