add some logging messages
BLXX-177 pause dark current collection until last acquisition finished

in case det rates view is busy collecting its last integration
BLXX-177 clear the times array during the stop() method also

this is always called when a scan finishes, when it is only sometimes
called when a scan aborts - depending on who sees the
InterruptedException and so how it is thrown.
Merge branch '8.34' of ssh://dascgitolite@dasc-git.diamond.ac.uk/gda/gda-core.git into 8.34