Fix Makefile so pdf docs build out of the box.

Fix small numpydoc bug so docs build out of the box. Already asked on numpy list if the fix is OK to upstream.

[merge] Typo fix.

Merging with upstream

added default behavior, to allow for unhandled backends, such as 'MacOSX'

Merging Brian's trunk-dev. * Fixed Foolscap import warnings (#525805). * Improved Monte-Carlo options pricing example.

Merging upstream.

Add notes by Brian on Mathematica notebook format.

Add doc about the format for storing interactive sessions. The idea is to use a notebook-like representation, but using plain rst for storage, with a few added directives of our own.

Fixed foolscap imports. As of Foolscap 0.4.3, foolscap introduces a foolscap.api module that all top-level symbols must be imported from. Fixes https://bugs.launchpad.net/ipython/+bug/525805