Bug: SOAP reports centres outside of box

[kyleaoman]

Seems like there are probably some places where the box should be wrapped before writing output, for example:

>>> import h5py
>>> import os
>>> base = "/cosma8/data/dp004/colibre/Runs/L0050N0376/Fiducial_test/SOAP"
>>> snapfile = os.path.join(base, "colibre_with_SOAP_membership_0127.hdf5")
>>> soapfile = os.path.join(base, "halo_properties_0127.hdf5")
>>> f = h5py.File(soapfile, "r")
>>> com = f["BoundSubhalo/CentreOfMass"][...]
>>> com.min()
-0.017256109013965164
>>> com.max()
50.00512234260799
>>> f["Header"].attrs["BoxSize"]
array([50.00000002, 50.00000002, 50.00000002])