Re-land r29957 (add versions and constraints for packages and samples), with

SDK constraints bumped from 1.0.0 to 0.8.10+6 .

R=ricow@google.com, sigmund@google.com

Review URL: https://codereview.chromium.org//62473002

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge/dart/pkg/mime@29986 260f80e4-7a28-3924-810f-c04153c831b5