Enhance plotting functionality of plot slice wrapper

[ahmadnish]

Hello :), so I wanted to instantiate pull requesting again with a minor fix now that I am working with matRad (actually, pyRadPlan) more often. I noticed that example2 tries to assign titles to the plotSliceWrapper, but they were getting masked by the axis settings.

[wahln]

Thanks for that.
I will not merge this onto master. Instead, as soon as @SimonaFa has finished her refactor of the plotSliceWrapper into plotSlice in #818, I will merge your developments into #818 and merge everything into dev.

[github-actions]

This PR was automatically marked as stale it has been open 30 days with no activity. Please review/update/merge this PR.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 0.00%. Comparing base (d5bd5bb) to head (3c34966).
Report is 9 commits behind head on master.

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##   master   #831   +/-   ##
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[wahln]

@SimonaFa since I just merged #818 could you check this pull request by @ahmadnish and see if we need to make some adaptations?

[github-actions]

This PR was automatically marked as stale it has been open 30 days with no activity. Please review/update/merge this PR.

[wahln]

This has been translated to the new matRad_plotSlice function (which uses key-value argument pairs instead of the long sequence of optional arguments) and merged onto dev in #854.
Since @SimonaFa used your implementation as a basis, I have added you as a co-author on the squashed merge commit. Will close this PR.