Updates for library changes, dart.js location, remove symlinked directories

Hi! This CL:

- updates some of the dart code to the latest library changes (dart:html using streams)
- updates the html files to reference dart.js from a package location and not the svn repository
- remove the packages subdirectories. These are symlinked directories and (AFAIK) shouldn't be committed to source control
- adds a .gitignore file