Squashed commit of the following:

commit 6977a8e410be5e0c2b44d5708e52bc6d431ba7ee
Author: Paul Prince <paul@littlebluetech.com>
Date:   Mon Jan 20 02:12:55 2014 -0500

    Bug fixes.

commit 4a0b9b1bdda87cfa0512a393384f60513ee229dc
Author: Paul Prince <paul@littlebluetech.com>
Date:   Sun Jan 19 22:31:59 2014 -0500

    Bump version.

commit 785413106c7091994697fab126dc550d96fc790f
Author: Paul Prince <paul@littlebluetech.com>
Date:   Sun Jan 19 22:28:28 2014 -0500

    Add CONTRIBUTORS file.

commit 4d36c7fc3745416df5d1b84fea0f2beda45429b6
Author: Paul Prince <paul@littlebluetech.com>
Date:   Sun Jan 19 22:23:34 2014 -0500

    Add check for .npm inside venv.

commit 189ee68abd1e740da89231ff5e8faf2278e42e73
Author: Paul Prince <paul@littlebluetech.com>
Date:   Sun Jan 19 21:38:55 2014 -0500

    Commit the initial meat of my improvement.

    Differences in behavior from upstream version:

      * Both the values, **and the set/unset** status, of
        all environmental variables will be preserved and
        restored properly on deactivating the virtualenv.

      * Also corrected an incorrect comment.