Adjust plotting limits
Remove Prochaska dN/dX and Omega_HI, as they are also SDSS, so not really independent measures of systematics
Implement computing the HI mass weighted distance in x for each DLA, and doing halo assignment from that
Use sorting of the particles to make things faster
Adjust makefile and comments for sorted arrays
Tweak plots
Compute the zdirection on the whole grid
Tweak plots
Allow specifying colour for sigma_DLA
Plot tweaks
Use C++ compiler
Only do particles that are neutral for the zdir
Fix silly bugs
Do not bother taking logs, fix the dimensions of the array,
and check that they stay fixed
Optimisation because now we are only within one halo at a time
Make a zerod grid in a less silly way
Compute distance weights in the right direction, and do a consistency check in the code
Since we now have a z direction, DLAs will not reside in multiple halos.
Therefore, once we have a halo for a DLA, quit the loop. Also build an
index of the DLA positions so that we have a reasonable place to start
from.

Now, eliminate an extra argument from find_halo_kernel for the halo
mass.
Merge branch 'master' into zdirsigma

Conflicts:
	make_feedback_cddf.py
Assign DLAs to halos if they are within 2 virial radii.

Walk through the halos in mass order. This is actually fast because the
largest halos have the most DLAs, but do it because DLAs can now easily
be within 2 r_vir of multiple halos.