Idiomatic FFT(W) Wrapper

[Per Nordlöw via Digitalmars-d-learn]

Have anybody constructed an idiomatic D wrapper for FFTW?

http://www.fftw.org/fftw3_doc/Tutorial.html#Tutorial

I'm specifically concerned about

- `RefCounted`-wrapping of the C structures `fftw_complex` and 
`fftw_plan`
- range semantics, lazy evaluation and caching of result in
   stream-based architectures; `fftw_plan`, `fftw_execute`
- slicing and scope
- seamless interoperability with Mir 
(https://github.com/libmir/mir)