In Rgui for Windows, this.path() works by looking at the windows
handles belonging to that R process.

For an open script, the windows handle will end with " - R Editor" OR
ANY SUPPORTED TRANSLATION INTO ANOTHER LANGUAGE. For a new script, the
windows handle will be "Untitled - R Editor", again possibly translated
into another language.

What we do in "main.R" is:

  * launch a new Rgui process in each supported language and each C
    Runtime (Microsoft Visual C++ Runtime and Universal C Runtime)

  * open an existing script and grab the translation of " - R Editor"

  * open a new script and grab the translation of "Untitled - R Editor"

We will then save that information into files "r-editor_msvcrt.txt",
"r-editor_ucrt.txt", "untitled_msvcrt.txt", and "untitled_ucrt.txt".
