Set the cython compiler directives with language_level attribute to avoid error with python 2.7.13.

/usr/lib64/python2.7/site-packages/Cython/Compiler/Main.py:367: FutureWarning: Cython directive 'language_level' not set, using 2 for now (Py2). This will change in a later release! File: /.../faust/build_FaustLinuxPython/wrapper/python/FaustCorePy.pyx

wrapper/python/setup.py.in

@@ -42,10 +42,12 @@ else: # linux and mac
                         extra_objects = @PYTHON_EXT_EXTRA_OBJECTS@
                        )
 
+
+
 setup(
     name = 'pyfaust',
     version = version, # cf. header
-    ext_modules = cythonize(PyFaust),
+    ext_modules = cythonize(PyFaust, compiler_directives={'language_level': sys.version_info.major }),
     packages = [ 'pyfaust' ],
     url = 'http://faust.inria.fr',
     description = 'TODO',