BREAKING CHANGE
Stop supporting http module in Dart. This is because Dart has a
well developed http package which should be used by Dart
customers instead.
This implementation only works in JavaScript, while the Observable transpilation
story gets worked out. Right now, the service just makes a simple request,
and returns an Observable of Response.
Additional functionality will be captured in separate issues.
Fixes#2028
Limitations because of preview status (see #960):
- does not yet use ShadowDOM
- does not use a builtin conditional like `if`
- uses a temporary bower repository
Closes#943