First release.
possum_physiology() and possum_operative() score the twelve physiological
and six operative variables; possum() and p_possum() turn those scores
into predicted morbidity and mortality.possum_risk() scores a whole cohort from a data frame in one call. A row
with a missing or out-of-range value is returned as NA and reported in a
warning, rather than aborting the whole cohort.cr_possum() (colorectal), v_possum() (vascular) and
raaa_possum() (ruptured aortic aneurysm), with their own scorers where the
cut-points differ.