add babelmixr2

[mattfidler]

This adds the commercial options from babelmixr2

[bbolker]

PS thanks for the contribution! (I forget: is there a PK task view either in existence or in prep??)

[mattfidler]

PS thanks for the contribution! (I forget: is there a PK task view either in existence or in prep??)

There is a PK task view; https://cran.r-project.org/web/views/Pharmacokinetics.html

[mattfidler]

I hope I got everything you suggested. Thanks for the edit!

[bbolker]

didn't fix typo in "Pharmcokinetic" (which I also wouldn't capitalize). (Sorry, I would fix this myself, but not 100% clear on how to make edits on PRs ...)

[mattfidler]

Great catch