Add random sort order for paths

[ianstormtaylor]

Sometimes I run into situations where I want to plot paths in a randomly shuffled order—often to prevent paper tearing/bleeding when many paths are drawn very close together.

Right now I do this in code before saving the artwork, but it would be nice to be able to do this in post right before plotting (or after plotting the first time and discovering that sorted paths caused an issue).

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Another option for a sort order could be interleaving—skipping every other path, and returning to the skipped ones in a second pass, allowing time to dry—for situations where the randomness of a shuffle would result in some still being too close together.

Just more generally it would be nice to have a few different sort orders to choose from based on the medium/content.