warnings building TomoPhantom on the VM

[KrisThielemans]

These look suspicious, especially the language level

ompiling src/TomoP2D.pyx because it changed.
[1/2] Cythonizing src/TomoP2D.pyx
/home/sirfuser/.local/lib/python3.6/site-packages/Cython/Compiler/Main.py:369: FutureWarning: Cython directive 'language_level' not set, using 2 for now (Py2). This will change in a later release! File: /home/sirfuser/devel/buildVM/builds/TomoPhantom/build/Wrappers/Python/src/TomoP2D.pyx
  tree = Parsing.p_module(s, pxd, full_module_name)
[2/2] Cythonizing src/TomoP3D.pyx
/home/sirfuser/.local/lib/python3.6/site-packages/Cython/Compiler/Main.py:369: FutureWarning: Cython directive 'language_level' not set, using 2 for now (Py2). This will change in a later release! File: /home/sirfuser/devel/buildVM/builds/TomoPhantom/build/Wrappers/Python/src/TomoP3D.pyx
  tree = Parsing.p_module(s, pxd, full_module_name)
/usr/lib/python3.6/distutils/dist.py:261: UserWarning: Unknown distribution option: 'zip_safe'
  warnings.warn(msg)
/usr/lib/python3.6/distutils/dist.py:261: UserWarning: Unknown distribution option: 'include_package_data'
  warnings.warn(msg)

[KrisThielemans]

FYI, we install cython via pip now (with python3)

[KrisThielemans]

no such warning for astra