Stop emitting dart2js's .precompiled.js file.

dart2js itself will stop emitting this file soon.

R=rnystrom@google.com

Review URL: https://codereview.chromium.org//701283002

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@41534 260f80e4-7a28-3924-810f-c04153c831b5
Add a Client class to json_rpc_2.

R=rnystrom@google.com

Review URL: https://codereview.chromium.org//691053006

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@41535 260f80e4-7a28-3924-810f-c04153c831b5
Add StringScanner.substring.

R=rnystrom@google.com

Review URL: https://codereview.chromium.org//701723002

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@41536 260f80e4-7a28-3924-810f-c04153c831b5
Bump pub_semver.


git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@41537 260f80e4-7a28-3924-810f-c04153c831b5
Add support for ^ constraints in pub.

R=rnystrom@google.com
BUG=17172

Review URL: https://codereview.chromium.org//686323002

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@41538 260f80e4-7a28-3924-810f-c04153c831b5