Added README and LICENSE. Updated pubspec.
Added numbers, json, and uri recipes to book
Added drone.io badge
Updated README.md
Added .buildlog to .gitignore
Reordered dependencies
Web UI templates recipes (first group of several).

Review URL: https://chromiumcodereview.appspot.com//13770011
Removed the book.asciidoc doc because it messes up Atlas
Merge branch 'uri' of https://github.com/dart-lang/cookbook into uri
Fixed typo.