Add chunk function to split array into smaller

[karelbilek]

this was a function that I found helpful to have.

I tried to follow your style.

[technosophos]

Should the order of arguments be reversed? One of the things we've tried to do is make it easier to pipe data from one command to the next. Doing tuple 1 2 3 4 5 | chunk 3 feels a little more ergonomic than using a variable in between.

[karelbilek]

Oh sure. I rarely use piping and use vars instead so I forgot about this usecase.

[karelbilek]

changed, rebased

[technosophos]

Looks great! Thank you.