Ignore some packages on readthedocs

conf.py

@@ -0,0 +1,10 @@
+import sys
+from mock import MagicMock
+
+class Mock(MagicMock):
+    @classmethod
+    def __getattr__(cls, name):
+            return MagicMock()
+
+MOCK_MODULES = ['pyfft', 'pyopencl', 'quantities', 'numpy', 'scipy']
+sys.modules.update((mod_name, Mock()) for mod_name in MOCK_MODULES)

requirements.txt

@@ -1,3 +1,4 @@
+mock
 numpy>=1.6.1
 quantities>=0.10.1
 pyopencl>=2012.1