Add depend on the GitHub versions of unittest and matcher.

R=sigmund@google.com

Review URL: https://codereview.chromium.org//797363004

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@42496 260f80e4-7a28-3924-810f-c04153c831b5
Remove unittest and matcher from the repo.

This also cleans up a few lingering unused lines in pkg.status.

R=sigmund@google.com

Review URL: https://codereview.chromium.org//814953002

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@42497 260f80e4-7a28-3924-810f-c04153c831b5