run jetty on dependency resolved war in gradle

Background:

• test classes(such as selenium tests) are in an independent module(maven project, etc.).
• have an external dependency(mave, ivy, etc) to war file(s)
• want to run jetty on dependent war file(s)

Gradle can start up jetty on dependency resolved war file(s).

When you want to run your tests after jetty started, set "daemon=true" and make the test task depends on your new run-war task.