Merge remote-tracking branch 'origin/feature/8971_cancel_algs_from_script'
Merge remote branch 'origin/bugfix/9087_savenxspe_nan_propertydefault'
Merge remote-tracking branch 'origin/feature/9174_plotpeak_additional_output'
Fix inheritance hierarchy of LegendWidget in qti.sip declaration

It was wrongly stated that it inherits from QObject so that the
Python type was showing up as QWidget & not the leaf class LegendWidget
Refs #7142
Merge branch 'bugfix/7142_qtiplot_python_cmds' into develop