Relicense from the Eclipse Public License 1.0 to version 2.0

As listed in the EPL-2.0 FAQ, advantages of switching include:
- The term of art is now referred to as "file" rather than "module";
- The choice of law provisions has been removed;
- The license is now suitable for scripting languages such as
  JavaScript; and
- The license now includes an option to add a secondary license for
  GPL-2.0+ compatibility.

The last point is particularly interesting for projects licensed under
GNU GPL-compatible licenses, such as the Common Desktop Environment,
which embed the Korn Shell.

The justification for this change is found within the original AST
license:

  "Contributor" means any person or entity that distributes the Program.

  ...

  The Program (including Contributions) may always be distributed
  subject to the version of the Agreement under which it was
  received. In addition, after a new version of the Agreement is
  published, Contributor may elect to distribute the
  Program (including its Contributions) under the new version.

The EPL-2.0 FAQ clarifies that the appropriate action for contributors
to re-license an EPL-1.0 work is to update file headers and notices:

  The EPL allows new versions of the license to be adopted by projects
  with little work. . . For open source projects (including Eclipse
  Foundation projects) under the EPL-1.0 who wish to re-license to the
  EPL-2.0 they should do so by simply updating the file headers and
  notices.

Please open an issue should there be any other references to the
Eclipse Public License 1.0.

References

Original AST license:
https://web.archive.org/web/20150527152850/http://www2.research.att.com/~astopen/download/licenses/epl-1.0.html

EPL-2.0 FAQ:
https://www.eclipse.org/legal/epl-2.0/faq.php