#57 squarefilled plot type

[legolas_a20]

Please consider adding a plot type that looks like a 'squared' plot, but filled below the line like an area graph. Another way to describe that would be to have an area graph but with straight lines like the squared graph has. Visually, what I'm looking for is the grey and blue areas you can see in these graphs:
https://confluence.atlassian.com/download/attachments/391087323/gh_6-2-1_version-report.png?version=3&modificationDate=1424670733345&api=v2
https://marketplace-cdn.atlassian.com/files/images/com.pyxis.greenhopper.jira/c51ef28a-4540-4e7b-9028-da45eebcb17c.png
A nice option would be to have the line in a different color than the fill (like in the examples).
Also discussed in this discussion.

[lbayuk]

Code changes have been committed to SVN to implement 2 new plot types: 'squaredarea' and 'stackedsquaredarea' (analogous to 'area' and 'stackedarea', but with squared line boundaries). New test scripts have also been committed. Documentation updates are in progress.

[lbayuk]

Implemented in 6.2.0