Run Play application in plugin test runner.

Many Play libraries depend on Play application. Some of them don't work
if there's no running application. There's currently none in plugin test
runner, which prevents some API working. This patch runs a default
application in the test runner to fix the problem.
Terminate MongoDB and ZooKeeper process after launchers stop.

Beyond currently launches standalone MongoDB and ZooKeeper. So, they
need to be terminated after the launchers stop.
Add test case for ScriptableCrypto.

It tests every static method in the module.