Move data.table to Imports

[MichaelChirico]

Thanks for using data.table!

I'm filing because we strongly discourage using {data.table} as Depends (in fact I strongly discourage Depends in general besides of course for R). This is something we track: Rdatatable/data.table#3076. See also the vignette on importing data.table: https://cran.r-project.org/web/packages/data.table/vignettes/datatable-importing.html.

If you'd like any help migrating, please feel free to reach out. The most common hang-up in my experience is (possibly) needing explicit library(data.table) in tests/vignettes. Blanket import(data.table) in NAMESPACE is the easiest fix for the package code itself, though I do encourage selectively importing only what's needed.