Testing for sorted data in integrate.trapezoidal cuts runtime in 1/2
when xnorm is sorted (which it always is) - Rprof() trapped this. Plus
this function was somehow being called in another file where it was
defined as was NZD I suspect so placed them in util.R
New function integrate.trapezoidal.sum that computes only the sum not
the cumsum... shaves a bit more off... down to 8.3 seconds from 19.1