Note about f2n

[mtewes]

@vbonvin @martin-millon This is just to let you know that I've started a new implementation of f2n:
https://github.com/mtewes/f2n
It is a bit different, and not a 1-to-1 replacement, but should also be much more flexible.
Feel free to add issues if you are interested, I'm also happy to give you write access to the repo.