Requeset: SAV SPSS files support

[giladfeldman]

Not a must, but would love it if we could run this on SPSS .SAV files. Tidy's haven imports those easily, so I guess it's not more than adding a few lines of code, but maybe I'm not considering something tricky.

We use those (mainly in Qualtrics exports) because they’re far better structured and have fewer issues (like with text including line breaks, commas, etc.). Fields should be fairly similar regardless of file formats, I imagine.