python3 support for numpy
python3 support for pillow
audit numpy
python3 support for scipy
python3 support for matplotlib
scipy+numpy: Reword openblas option
numpy: reword message if numpy-site.cfg is there.
numpy: Simplify caveat
numpy: Update resource 'nose' to 1.3.1
scipy: --with-python3 needs numpy --with-python3
matplotlib: style bit
matplotlib: pygtk only for python 2.x right now
README: Remove outdated note about -py3 suffixes.

Gladly Homebrew/core took the sane route of restoring python 2.x and
3.x support with a helper method.
README: Clarify Troubleshooting.