Example multi-language pipelines

Example 1 - JavaPrefix: A python pipeline that reads a text file and attaches a prefix in Java side to each input.
Example 2 - JavaCount: A Python WordCount example that utilizes a Count transform in Java side.

Instructions for running the pipelines

Start the expansion service by running script start_expansion_service.sh
To run the pipeline using DirectRunner, run corresponding run_<example>_direct.sh script.
To run the pipeline using DataflowRunner,
- Follow the instructions here to setup a GCP project
- Open the corresponding run_<example>_dataflow.sh script
- Update the enironment variables at the top of the script.
- Save and run the script.