Merge remote-tracking branch 'origin/feature/7022_alg_dialogs'
Merge remote-tracking branch 'origin/bugfix/7036_osx_plot_axes'
Merge remote branch 'origin/7035_powder_reduction_MPI'
Merge remote-tracking branch 'origin/feature/7051_rhel_multiple_cmd_args'
Re #5934. Move the TESTHISTOLISTENER instrument to the TEST facility.

This stops it appearing in the list of ISIS instruments in the
first-time setup dialog and elsewhere.
Merge branch 'bugfix/5934_hide_testhistolistener' into develop