* 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
New conservative transfer function scheme.
New random number generator that preserves coarse Fourier modes instead of applying Hoffman-Ribak
Some minor bugs fixed.
* Moved hybrid poisson solver from convolution_kernel.cc to poisson.cc
* Fine-tuned deconvolution schemes for various running modes
* Added lots of doxygen documentation
Note to myself: don't fix signs while listening to talks!!
Other mods/fixes:
* 2LPT is now supported also with distinct baryon/DM
power spectra. This creates now an overhead when
using Eisenstein&Hu or BBKS. But who cares.
* Reverted to determinant formulation of LLA rather than
second order expansion. This is much more accurate.
* Added baryon density filter. Baryon density field is now
consistent with CIC DM density. This is achieved by
convolving with an additional grid cell filter (and
no deconvolution).
* Tested LLA, skewness is now exact to a few per cent
but tends to be systematically higher.
* 2LPT needs a bit less memory now in multigrid mode
(FFT based 2LPT still needs humongous amounts).
* Cleaned up code output.
* The DM transfer function is now deconvolved with the cell assignment
function in order to restore power near the Nyquist wavenumber.
* Added an option to change the random number sample cube size
[random]/cubesize. This should be set >128 to generate un-
correlated numbers. True fix pending.
* Removed some unused code
* Increased Buffer size for Gadget-2 output plug-in
