How to best set the filenames of VFs

Currently we name VFs filenames as `Family-Regular.ttf`

I think filename `Family-Roman.ttf` and `Family-Italic.ttf` is better, especially as esteemed superuser @thlinard, @eliheuer and others have pointed out (at https://github.com/google/fonts/pull/1814#issuecomment-454889240 and elsewhere) that `Family-Regular.ttf` (400 static) is confusable with `Family-Regular.ttf` (roman VF)

Also, if the file is named differently on Github, will the download-ZIP get a renamed file?

For now, Marc has set up PRs for VFs with "normal" names (`Family-Regular.ttf`) and I'm going to merge these, with static fonts in each family's subdirectory, but @rsheeter suggested on a IM chat to file this separate issue to ponder VF file naming, as it's very much something we can alter and the GF eng team has not yet fully considered it.