FFTW not enabled on Windows

Not really a proper feature request but FFTW will need to be enabled on Windows to build the remote module diapotb.

One quick way to do it is to bump SuperBuild FFTW version from 3.3.4 to 3.3.8, which contains a CMakeLists.txt. It will simplify the compilation on Unix and Windows platforms.

The other way is to try to download binaries for windows only. It tried to ones given here but the links seem broken.