Added the ability to process up to three spaxels (spectra). Current issues w/ performing continuum subtraction for more than 1 spaxel.
Added test for multiple spaxel pairs, w/ and w/o continuum subtraction. Currently, continuum subtraction w/ several spaxels fails.
Reflects addition of processing multiple spectra (up to 3). See commits for ifu_1d_spectrum() for this date.