move getattr() utility code from Builtins.c to ObjectHandling.c as it deals with object protocols and is not a required replacement

remove another reference to the old distutils build (in quickstart!) and clarify the description of the Sage notebook a bit

--HG--
extra : rebase_source : 305a362b2f79e4b7982a188ff5912a6621ea56a7

Do not abort .pxd processing due to previous unrelated errors.