* Updating udunits.
Udunits 2.2.21 is no longer on the unidata ftp site.
The latest is 2.2.23, adding that and it's md5sum.
* Updating udunits2 download URL.
The Unidata ftp site does not keep previous versions of udunits.
However all the tagged versions are in their github.com repository.
Updating the URL to use github.
* Updating udunits2 with a autoreconf def.
The udunits packages on github do not contain a configure script.
One has to run autoreconf to generate it, so adding that to
package file.
Also updated to the latest version and all md5 checksums.
- 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
* Remove +mpi variant from NCO
* Update NCO deps to AutotoolsPackage
* Update the other NetCDF packages to AutotoolsPackage
* ANTLR has a nolink deptype on java, don't worry about csharp
* Remove restrictions from NCO package, fix homepage
* Add version 4.6.3 of NCO
* Missed AutotoolsPackage for NetCDF-CXX4
* NetCDF tests fail when run in parallel
* Remove commented out dependency
* Add documentation dependency
