cows have mitochondria, who would have guessed; also, pull some stuff out of plink_common that has no business being there
start purging remaining unnecessary global variable references from multithread inner loops
groupdist bugfix
distance writer cleanup
--genome write cleanup
--genome cleanup finished
--rel-cutoff cleanup
--make-grm-bin cleanup
done cleaning up plink_calc
spawn_threads2() on assoc/model adaptive
--assoc/model max(T) switchover
oops, forgot about fewer-threads corner case