For CAS-14348:
1. In DelayRateFFT.cc's DelayRateFFTConcat class:
(a) Reordered working array (Vpad_) axes to put time and freq before corr and ant (Fortran order) so they are contiguous for 2d FFT;
(b) Introduced direct use of fftw (instead of LatticeFFT) thereby drastically improving performance of the FFT stage; by (mainly) avoiding unnecessary copies;
(c) Improved array slicing to streamline (unavoidable) data copies into the working array;
(d) Introduced Double precision weight sum accumulation (copied to Single precision at the end), and streamlined weight accumulation code to make it clearer;
(e) In snr calulation use amplitude found in searchPeak instead of relocating it via calculation from delay/rate solutions;
(f) Various other code clean-up and minor re-org.
2. In FringeJones.cc: Logging improvements for readability, and introduced fringefit stage solving time measurements and logging.
3. In Calibrater.cc: Occasionally (every ~10%) report solution count progress, and don't log useless solution quality stats for FringeJones (they are not yet filled correctly)
