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
```
for avro, yes. ref [install_requires.append('simplejson >= 2.0.9')](http://svn.apache.org/repos/asf/avro/trunk/lang/py/setup.py)