issue-1: issue-2: Chain extension virtualenvs in sys.path and in PATH.
issue-4: fix current_python_interpreter() kludge.
Make a more helpful error message in ve-extend when the destination e…
…nvironment does not exist.
Make script.copy() preserve symlinks.
Change the package name.
Updated README and permanently change the version to "latest".
Ignore build directories, update README with blog post, bump version …
…number for next release.
A few more README tweaks
Update the README