* Updated all Python extension packages to use 'setup_py' on install.

* Fixed a few minor style issues with the updated Python packages.

* Warn user if flake8 can't find setuptools

* Add missing dependencies of flake8

* Updates to py-autopep8, make packages activateable

* Check for presence of setuptools for Sphinx too

* Fix bug in order of commands

* Run make clean to prevent warning messages

* Don't delete temporary files after completion

* Remove duplicate ICU package

* Ignore deleted files during flake8 tests

* Rename Boost ICU variant

Enable sh emulation for Zsh and allow loading modules recursively.

spack module :
- refresh accepts a constraint
- find and refresh share common cli options
- ask for confirmation before refreshing
- deleting the module file tree is now optional

Updated the 'scotch' package to use oneline 'variant' directives.

Updated the Scotch package to conform to PEP8 standards and to test style checking improvements.

- was missing the obvious.

- Exempt overlong URL lines from checks.
- Omit some of the more painful PEP items.

I addressed them by factoring the code better to follow the visitor
pattern.  This will allow actions to be easily added in the future.
These may not even be file sytsem views.  One could add actions to
generate shell init scripts, JSON DAG-dumpers, GraphViz DOT file
generators, etc (yes, some of these are alread in there - just to give
the idea).

Also added is a top-level test

 $ source share/spack/setup-env.sh
 $ ./share/spack/examples/test_view.sh

Read the top of that script first.

remove the part I added to setup-env.sh as this does not work unless the modules package is already built.