Add gcl presubmit script to the dart src tree.
Add gcl presubmit script to the dart src tree.

Currently I just added a tree status check but we can extend this over time.
Review URL: https://chromiumcodereview.appspot.com//10891021

git-svn-id: c93d8a2297af3b929165606efe145742a534bc71@11575 260f80e4-7a28-3924-810f-c04153c831b5

dart-lang/sdk,dart-lang/sdk,dartino/dart-sdk,dart-lang/sdk,dartino/dart-sdk,dart-archive/dart-sdk,dart-lang/sdk,dartino/dart-sdk,dartino/dart-sdk,dart-lang/sdk,dart-archive/dart-sdk,dart-archive/dart-sdk,dart-lang/sdk,dart-archive/dart-sdk,dart-lang/sdk,dartino/dart-sdk,dartino/dart-sdk,dart-archive/dart-sdk,dart-archive/dart-sdk,dart-archive/dart-sdk,dartino/dart-sdk,dartino/dart-sdk,dart-lang/sdk,dart-archive/dart-sdk,dart-archive/dart-sdk,dartino/dart-sdk