"Use the same window" option for MuonAnalysis

[mantid-builder]

Original Reporter: Arturs Bekasovs

On the settings tab, add another option, which when enabled would make the interface use the same (effectively the previous) window for plotting. This should solve the problem of the new graph appearing in an unexpected place all the time.

However, sometimes it is useful to keep the previous graph as well. So the trial solution agreed on by the scientists is to copy the old graph to the new window.

[mantid-builder]

This issue was originally trac ticket 9051