Use a bit.ly link to link to the codelab
git ignore another file
Upgraded web_ui
Updated for libv2

Things are still broken. See:
http://stackoverflow.com/questions/14533092/cannot-find-referenced-source-packageweb-ui-web-ui-dart/14533094#14533094
Update the code lab for Dart M4.
Merge pull request #4 from dart-lang/update-for-m4

Update the code lab for Dart M4.