Update ignored paths
Import debugging and optimizing
Integrate the notes on profiling and optimizing
Rework the intro and the workflow
Add visible authors and link to github
Restructure the advanced numpy chapter
advanced/python: add a new chapter
sphinx: turn on the intersphinx extension

The link for python documentation is changed to point to python 2.x line.
MISC: cosmit in advanced_numpy
WIP in image processing
Add image_processing in index
Add link for downloading a zip of the latest (master) html version
+ source and extra files
Merge branch 'master' into image_processing
Improve the pyflakes section
advanced/python: typos found by spellchecker
advanced/python: minor rewording suggestions
advanced/python: fix functool.update_wrapper example
advanced/python: markup for contextlib.contextmanager example
advanced/python: describe property and other corrections

As suggested by Valentin.
advanced/python: doctest fixes