Add non-Rstudio extension transform option.

[MilesMcBain]

It would be nice to offer a transform at the file level for non-rstudio users. There is probably code that can be stolen from deplearning, packup, and mmmisc to piece this together.

[nathaneastwood]

An idea for a possible extension that would be accessible to all (internet using) users would be a Shiny app. Something like the stringr explorer or tidyshiny.