Add test data file which is 'deflated' and 'multiblocked'.
Update test data files.
Add 'eavro_util' module which contains helper functions.
Bugfix: incorrect array and map encoding when are empty ones.
Union value now decoded into tagged with its real type value, i.e. into tuple {Type, Value}, this done to avoid a set of ambiguity problems for client.
Add function to encode avro_type() into JSON. This required to write OCFs header.
Add test for schema encode/decode to/from JSON.
Adjust tests for new way of Union values return.
Implement writing of OCFs.
Add tests for writing OCFs (deflated, multiblocked etc).