* DOC: redistribute docstring-only content from numpy/doc

* DOC: post-transition clean-up

* DOC, MAINT: reskip doctests, fix a few easy ones

* Make clear that "trailing" means the "rightmost" dimensions.
* Instead of saying "works its way forward" (forward?), say
  "works its way left".

As numpy is Python 3 only, these import statements are now unnecessary
and don't alter runtime behavior.

* DOC: clarified rules about broadcasting when empty arrays are involved.

Replaced <type 'exceptions.ValueError'> with ValueError in the
outdated broadcasting documentation

The exception details in the broadcast documentation were old and
have since been updated. This commit changes the documentation to
reflect the current exception details when a shape mismatch is
raised.