Make stocks-fn match the style for the Sky SDK

1) Add a pubspec.yaml.
2) Move all the code into a 'lib' directory.
3) Move the stock widgets out of the app's library.

TBR=eseidel@chromium.org

Review URL: https://codereview.chromium.org/1011023003
11 files changed
tree: f72cb1507481b90caf961184c5f8e74e64f4d285
  1. examples/
  2. packages/