Offer zip builds

If you go here:

https://cran.cnr.berkeley.edu/bin/windows/base

you see EXE installers for Windows. This contrasts with other programming
languages that offer both an executable installer and ZIP files that can be
extracted and run. For example Go:

We did offer both zips and an installer until 2001 or 2002.  It was 
decided then that it wasn't worth the trouble of offering both.

I don't recall anyone asking for the zip in the 17 years after that 
change, until now (though I haven't been paying attention lately, since 
I retired from building the binaries a couple of years ago).

If you think it's worthwhile to do it, then I don't think anyone would 
object if you went ahead and did so.

Duncan Murdoch