BLVIII-24 make more resilient to errors, prevent ConcurrentMoificationException in JythonServer, remove requirement to define the x and y points before the scan starts
BLVIII-24 prevent ConcurrentMoficationException

This would happen if observers deregister themselves inside thier update() method - which they might want to based on what events were sent.
CORE: Rix ConstantVelocityRasterScans to work on beamlines with concurrent detector readout configured
TwoDScanPlotter was plotting each point of the scan. To improve performance 
for fast scan the plot is updated with a rate of 1.2 s.
It will be upgraded soon to allow the control of the plot rate.
improve how continuous scan handles the final data points after motion has finished

includes a timeout

some code tidy up
improve daserver error handling when data socket becomes out of sync
Merge branch 'gda-8.40' of ssh://dascgitolite@dasc-git.diamond.ac.uk/gda/gda-core.git into gda-8.40
Merge branch 'gda-8.40' of ssh://dascgitolite@dasc-git.diamond.ac.uk/gda/gda-core.git into gda-8.40
Scans from last run of client are now selectable

Bug introduced in commit 6e3a17a1
Merge remote-tracking branch 'origin/gda-8.40'

Conflicts:
	uk.ac.gda.api/src/gda/jython/JythonServerFacade.java
	uk.ac.gda.client/META-INF/MANIFEST.MF
	uk.ac.gda.core/src/gda/device/detector/DAServer.java
fix merge error