[WIP] add avro schema to support other languages

Add [Apache Avro](http://avro.apache.org/) protocol schema for other [Supported Languages](https://cwiki.apache.org/confluence/display/AVRO/Supported+Languages).It was only a partial modification to the attempt. Not centain if such avro schema can fit this project.

```
$ nosetests test/test_avroproto.py
....
----------------------------------------------------------------------
Ran 4 tests in 0.002s

OK
```
Nice! We are feature-freezing for Beta 2.0 today, so I am moving this to the Beta 3.0 milestone. Once the feature-freeze is in place, please rebase the PR on the `develop` branch, fix the build and force-push. I will review as soon as possible.

Thank you for your contribution!