Add test case for ScriptableCrypto and etc

First of all, this PR's changed the plugin test runner to launch a Play application. It's because many Play modules depend on the Play app and without it it's impossible to test the modules.

After the change, I found that `mongod` for Mongo and `java` for ZooKeeper didn't stop after the test had finished. I see that launching the standalone processes is kinda temporary, but I think they need to be terminated until the temporary behaviour is fixed.

Finally, a test case for `ScriptableCrypto` is added.

@sgkim126 and @kimchoco, review this PR please.