LaTeX formatting issue in `fast_fourier_transform.ipynb`

[JelleLa]

Dear,

In the first cell of the PSD section, PyFar (Or matplotlib in the backend?) complains about the string formatting:

<>:5: SyntaxWarning: "\s" is an invalid escape sequence. Such sequences will not work in the future. Did you mean "\\s"? A raw string is also an option.`

LaTeX output looks fine, but warning is there nontheless. The "did you mean" suggestion does not resolve anything.

Jelle (from ASSA :D)

[JelleLa]

Solved in analog form with Marco, adding "r" (raw string) in front of the errornous strings works!
Time to properly clone the repo and make a pull request, I suppose...

[mberz]

Feel free to post a pull request on Wednesday ;)