Merge remote branch 'origin/feature/7979_RemoteJobConditionalBuild'
Merge remote branch 'origin/bugfix/8000_python_instrumenttest'
Merge remote-tracking branch 'origin/feature/7579_plot_using_selected_x'
Re #6494. Enable cancellation in case of erroneous input.

If the user inputs a log with a large range, print a warning and add
progress reporting and a couple of bonus spots where the algorithm can
be cancelled.
Re #6494. Handle variable deletion in a better way.
Merge branch 'feature/6494_sumeventsbylogvalue_cancellable_in_case_of_dumb_input' into develop