Cost function for Fluspect parameter fitting

Usage

COST_4Fluspect(params, measurement, input)

params: numeric vector of length 8, in order: Cab, Cdm, Cw, Cs, Cca, Cant, Cx, N - leaf biochemistry/structure parameters being fitted.
measurement: the observed (measured) spectrum being fitted against.
input: list of 6 elements, in order: leafbio (baseline leaf parameters), optipar (optical parameters), spectral (spectral configuration), include (0/1 flags per parameter, controlling whether each is fitted or held at its leafbio default), target, range.

rfl and tran resampled