FFT

This request contains a few corrections and updates to the 1D FFT labs.  There is an issue of what fftw package to use.  The lab assumes use of the package anfft currently.  Unfortunately, anfft is hard to install/unsupported on Mac although it is easy to use on Windows.  The package pyfftw is another option but is difficult to install on Windows.

I recommend that this gets merged to make sure the content changes are in place before I move and become less available, but someone familiar with the way the labs will be set up should make note of the package issue.