Add TestTranslator example from Spark

[stokito]

The Spark has a nice command line utility to test translator: https://github.com/igniterealtime/Spark/blob/cb972ae18cfd56b1814d929341c797827f73dfd9/plugins/translator/src/test/java/com/jivesoftware/spark/translator/TestTranslator.java

We can copy the example it into this sources (and remove there).