Test volume 20
================

Volume error reported in https://github.com/Normaliz/PyNormaliz/issues/20

>>> import PyNormaliz_cpp
>>> cone = PyNormaliz_cpp.NmzCone(**{'subspace': [], 'vertices': [[0, 0, 0, 1],
...  [0, 0, 1, 1], [0, 1, 0, 1], [0, 1, 1, 1], [1, 0, 0, 1], [1, 0, 1, 1], [1, 1, 0,
...  1], [1, 1, 1, 1]], 'cone': []})
>>> PyNormaliz_cpp.NmzResult(cone,'EuclideanVolume') - 1.0 < 0.01
True
