[Feature] - Add Tool Offset for aftermarket blades

[TestApp90]

There are some great aftermarket blades like the Roland Blade, but the knife offset is 0.25mm. The default inkscape plotter extension has the option to set an tool offset, but I could not find it in your extension. Could the logic for the tool offset be imported into your extension? There are three methods for the logic in hpgl_encoder.py (extension folder).

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[t0b3]

@TestApp90 sure, that's a great idea. Any PR introducing such a feature is welcome 👍

[mteep]

Note that the Graphtec cutting plotters, on which the Silhouette:s are based, handle blade offsets internally. It's just a matter of setting the correct offset for the tool. Since they use the same GPGL command language, this might work for the Silhouette:s too.