Modifications:
- added support for multi-valued variants
- refactored code related to variants into variant.py
- added new generic features to AutotoolsPackage that leverage multi-valued variants
- modified openmpi to use new features
- added unit tests for the new semantics
* Remove fake URLs from Spack
* Ignore long lines for URLs that start with ftp:
* Preliminary changes to version regexes
* New redesign of version regexes
* Allow letters in version-only
* Fix detection of versions that end in Final
* Rearrange a few regexes and add examples
* Add tests for common download repositories
* Add test cases for common tarball naming schemes
* Finalize version regexes
* spack url test -> spack url summary
* Clean up comments
* Rearrange suffix checks
* Use query strings for name detection
* Remove no longer necessary url_for_version functions
* Strip off extraneous information after package name
* Add one more test
* Dot in square brackets does not need to be escaped
* Move renaming outside of parse_name_offset
* Fix versions for a couple more packages
* Fix flake8 and doc tests
* Correctly parse Python, Lua, and Bio++ package names
* Use effective URLs for mfem
* Add checksummed version to mitos
* Remove url_for_version from STAR-CCM+ package
* Revert changes to version numbers with underscores and dashes
* Fix name detection for tbb
* Correctly parse Ruby gems
* Reverted mfem back to shortened URLs.
* Updated instructions for better security
* Remove preferred=True from newest version
* Add tests for new `spack url list` flags
* Add tests for strip_name_suffixes
* Add unit tests for version separators
* Fix bugs related to parseable name but in parseable version
* Remove dead code, update docstring
* Ignore 'binary' at end of version string
* Remove platform from version
* Flip libedit version numbers
* Re-support weird NCO alpha/beta versions
* Rebase and remove one new fake URL
* Add / to beginning of regex to avoid picking up similarly named packages
* Ignore weird tar versions
* Fix bug in url parse --spider when no versions found
* Less strict version matching for spack versions
* Don't rename Python packages
* Be a little more selective, version must begin with a digit
* Re-add fake URLs
* Fix up several other packages
* Ignore more file endings
* Add parsing support for Miniconda
* Update tab completion
* XFAILS are now PASSES for 2 web tests
