Give tests more time to start running.

Actually depend on path.

This releases 0.12.1.

R=kevmoo@google.com

Review URL: https://codereview.chromium.org//1134193004

Test runner.

Support asynchronous main methods.

This also releases 0.12.0-rc.1.

Closes dart-lang#92

R=kevmoo@google.com

Review URL: https://codereview.chromium.org//1107743002

Release 0.12.0-rc.0.

R=kevmoo@google.com

Review URL: https://codereview.chromium.org//1107493002

Fix running browser tests in subdirectories.

Custom HTML files, skip support.

Configurable timeouts, Safari support.

Support for Dartium, content shell, and PhantomJS.