BLVII (8.34) Fix Epics time series code to read current data.

It used to read out the data from the previous scan!
Merge branch '8.34' of ssh://dascgitolite@dasc-git.diamond.ac.uk/gda/gda-epics.git into 8.34
EPICS (8.34) Create AreaDetector Merlin driver that triggers a an energy
threshold sweep at each point in scan.
Merge branch '8.34' of ssh://dascgitolite@dasc-git.diamond.ac.uk/gda/gda-epics.git into 8.34
GDA (8.34) Fix EpicsTrajectoryMoveController to work with multinput scannables with an offset onjust one input
Merge branch '8.34' of ssh://dascgitolite@dasc-git.diamond.ac.uk/gda/gda-epics.git into 8.34
EPICS - Add checkDroppedFrames to NDPluginBase
EPICS - NDFileImpl Add timeout to startCapure
EPICS - PVValueCache Class to act as buffer to EPICS.

putWait - send updates over channel access if the value to send is different from
the value in the IOC.

get - returns value sent in last monitor callback
EPICS - CachedLazyPVFactory - support use of PVValueCache
Zebra - support calls to set PULSE block parameters. Use PVValueCache
EPICS - FileWriterBase - support checkErrorStatus
EPICS - MulitpleImagesPerHDF5FileWriter - check for errors during scans
EPICS - Support fix exposure step size in flyscan
EPICs - EpicsMotor - use caputWait when setting the speed
Zebra - change logging level in isMoving
ADViewer - remove getMjpegViewCompositeFactory from ADController
add setters to allow for arbitrary Plot View names
MXGDA-1599 Set isBusy flag in PVScannable.asynchronousMoveTo *before* doing the caput

Otherwise there's a risk (observed on I02) of the put callback coming back to
GDA, and isBusy being set to false, *before* isBusy is set to true. This causes
the scannable to get 'stuck' in the busy state and waitWhileBusy hangs forever.
PCOTFGTrigger - set acquire period