* fix an issue where --hot would not exit

* add type annotations

- [x] Refactor view support into separate classes.
- [x] Make the hot runner grab the main view and call runFromSource on it.
- [x] Remove Device.needsDevFS (because it is always true).

* send the base uri back to debuggers

* add a fullRestart parameter to app.restart

* add await

- [x] Update engine to bring in new snapshotter.
- [x] Use the new snapshotter to quickly determine the minimal set of files necessary to run.
- [x] On first DevFS sync, only sync files necessary to run the application.
- [x] Fix a DevFS unit test failure.
- [x] Include DevFS tests in all.dart.

* support hot mode from the daemon protocol

* move method params to constructor