fixed a minor error in cubes.integ: now respects Z-units (zunit keyword)
fixed a minor error in cubes.integ: now respects Z-units (zunit keyword)

tectronics/agpy,tectronics/agpy,jcesardasilva/agpy,jcesardasilva/agpy,jcesardasilva/agpy,ufoym/agpy,tectronics/agpy,Leotrinos/agpy,jcesardasilva/agpy,tectronics/agpy,Leotrinos/agpy,ufoym/agpy,Leotrinos/agpy,ufoym/agpy,Leotrinos/agpy,ufoym/agpy