TST: add another test for the number of channels
ENH+TST+DOC: add documentation to meeg_chan_neighborhood
BF: set proper assert statement for volume size
NF: check for neighborhood
Merge branch 'master' into _orient
Merge branch '_orient' into _meeg
MSC: use another neighborhood
Merge branch 'master' into _orient
Merge branch '_orient' into _meeg