Merge with master

The deprecation of Python2.6 and the insertion of environments made it quite difficult to merge.

test/test_evaluate/test_context.py

@@ -1,7 +1,7 @@
 def test_module_attributes(Script):
     def_, = Script('__name__').completions()
     assert def_.name == '__name__'
-    assert def_.line == None
-    assert def_.column == None
+    assert def_.line is None
+    assert def_.column is None
     str_, = def_._goto_definitions()
     assert str_.name == 'str'