add versions and constraints for packages and samples
add versions and constraints for packages and samples

- all packages at 0.9.0, except "analyzer" which had a version already
- dependencies at ">=0.9.0 <0.10.0" except analyzer is ">=0.10.0 <0.11.0"
- sdk constraint ">=1.0.0 <2.0.0"

R=sigmund@google.com

Review URL: https://codereview.chromium.org//59763006

git-svn-id: c53bd6455474c0a826d309663cf600546f7b0963@29957 260f80e4-7a28-3924-810f-c04153c831b5

dart-lang/watcher