atLevelStart() and atLevelEnd() to ScannableGroup
BLBXVI-40 add TogglerScannable to allow moving a scannable during another's scan events.
Added support for ZIE scannables for ScannableGroup
GDA-5906 - scan and pos commands now trigger atLevelEnd() on scannables
BLBXVI-40 Added ability to configure behaviour for stop() and atCommandFailure() events.
Added ability to revert toggled scannable to state prior to hooked event.
Added test for ZIE scannable in ConcurrentScanTest
Merge branch '8.38' into 8.38.mt
GDA-5956 (8.38 ONLY) Another temporary fix to deadlock in scan shutdown. PaulG has a better solution for master.
GDA (8.38) ScanBase now treats the property "gda.scan.clearInterruptAtScanEnd" as false by default restoring the 8.34 behaviour
Merge remote-tracking branch 'i07-prod/8.38' into 8.38

Conflicts:
	uk.ac.gda.core/src/gda/scan/ScanBase.java
Merge remote-tracking branch 'b16-prod/8.38.mt' into 8.38