adds the geocentric_distance parameter to kbmod.reprojection_utils.correct_parallax, which when set will use the provided value instead of getting the geocentric distance from the minimizer.
also makes the loc casting a little cleaner for both correct_parallax and invert_correct_parallax
also adds a test skip for a test that has a GPU call.
resolves #614
geocentric_distanceparameter tokbmod.reprojection_utils.correct_parallax, which when set will use the provided value instead of getting the geocentric distance from the minimizer.loccasting a little cleaner for bothcorrect_parallaxandinvert_correct_parallax