[GEM] Added gem skeleton
[libnova] Added Data::Date (ln_date)
[libnova] Added Data::DMS (ln_dms)
[libnova] Added Data::EllOrbit (ln_ell_orbit)
[libnova] Added Data::EquPosn (ln_equ_posn)
[libnova] Added Data::GalPosn (ln_gal_posn)
[libnova] Added Data::HelioPosn (ln_helio_posn)
[libnova] Added Data::HMS (ln_hms)
[libnova] Added Data::HrzPosn (ln_hrz_posn)