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.

They were declared as returning type `bint`, but this appears to be incorrect.

http://docs.scipy.org/doc/numpy/reference/c-api.array.html#PyArray_FROM_OTF

http://docs.scipy.org/doc/numpy/reference/c-api.array.html#PyArray_FROM_OT