Update Python recommended versions.

doc/requirements.inc

@@ -14,7 +14,7 @@ Requirements
 .. _pycuda: https://mathema.tician.de/software/pycuda/
 .. _skcuda: http://scikit-cuda.readthedocs.io/en/latest/
 
-    Python_ < 3.6
+    Python_ == 2.7* or ( >= 3.3 and < 3.6 )
         |PythonDistRecommended|. Python 2.4 was supported up to and including the
         release 0.6. Python 2.6 was supported up to and including the
         release 0.8.2. Python 3 is supported past the 3.3 release.