added some tests for Maps.__getitem__
added some tests for Maps.__getitem__

sdss/marvin,sdss/marvin,bretthandrews/marvin,sdss/marvin,albireox/marvin,albireox/marvin,bretthandrews/marvin,albireox/marvin,bretthandrews/marvin,sdss/marvin,albireox/marvin,bretthandrews/marvin