Closes #621

Closes #578

Closes #579

rev to analyzer 0.30.0

fix a few analysis warnings

Fixes https://github.com/dart-lang/test/issues/594

Runs the following tests:

- dartanalyzer
- dartfmt
- vm tests excluding all browser tags
- dartium tests

Note that the dev SDK appears to leave pub running after a successful run of tests. This will need to be investigated further.

Adding hooks for new reporters and test platforms. These hooks are not intended to be a part of the external API and thus are aptly documented.

* plumb chain-stack-traces configuration through

* correctly plumb new flag through and add corresponding tests

* add example command

* chains -> chained

Dartfmt *.dart