- Add a PythonPackage class with build system support.
- Support build phases in PythonPackage
- Add a custom sanity check for PythonPackages
- Get rid of nolink dependencies in python packages
- Update spack create to use new PythonPackage class
- Port most of Python packages to new PythonPackage class
- Conducted a massive install and activate of Python packages.
- Fixed bugs introduced by install and activate.
- Update API docs on PythonPackage
* py-markdown: Add new package for python-markdown.
* py-markdown: Added restrictions on Python version.
* py-markdown: Removed upper-limit on compatible Python versions.
* py-markdown: Reinstated upper bound on Python version. Also fixed small formatting error.
