Add shuffle mode

[darkdragon-001]

Similar to PDFtk, this should (1) split a file into multiple batches (specified by ranges) and (2) zip them back together. This allows to apply different rotations to even/odd pages.

[corollari]

Isn't this already achievable with the current version of stapler by using sel followed by zip?

[darkdragon-001]

(1) is blocked by #38 (even/odd pages)
(2) is available
and there is no way of combining the two steps in a single command without temporary files.

[corollari]

I see, what do you think of getting #38 done and then asking users to do apply the transformation by taking two steps (with temporary files, like you mentioned)? I'm not sure if there's enough demand to create a special command for only this use case.

[darkdragon-001]

When you duplex scan landscape pages, even and odd pages need to be rotated differently. I think this is a pretty common use-case and was the main reason I discovered PDFtk in the first place.