split_path(path)
Get the parent path and basename.
>>> split_path('/')
['', '']
>>> split_path('')
['', '']
>>> split_path('foo')
['', 'foo']
>>> split_path('/foo')
['', 'foo']
>>> split_path('/foo/bar')
['/foo', 'bar']
>>> split_path('foo/bar')
['/foo', 'bar']