* Fixed a bug in the coarse grid density correction that lead to a shift in the correction in some rare cases
* Fixed a bug in restricting fine grid noise when the double size fine grid (for FFT) is actually larger than the domain.
* Added new log file routines that use printf syntax
* Added log file output to most parts of the code
* Removed the stats file output, it is now appended to the log file
* Moved hybrid poisson solver from convolution_kernel.cc to poisson.cc
* Fine-tuned deconvolution schemes for various running modes
* Added lots of doxygen documentation