Compatibility with NBodyKit

[liamstaras]

We are using NBodyKit to calculate some power spectra, with FFTPower. However, this is much more cumbersome and archaic than powerbox, and we were wondering if having a similar kmin/kmax feature. NBodyKit uses these in its automatic bin creation routine, and it would be great to have something similar in PowerBox, so it could act as a drop in replacement! Many thanks.

[steven-murray]

That certainly sounds like something we could add! Unfortunately my time is very limited at the moment -- do you think you could make a PR? I could review it and help with implementation details.