I've added support in the C library for getting the JSON encoding of an Avro value. There are three patches in this series. One of the changes is to upgrade our copy of the Jansson library to 1.3. (All of the existing test cases pass with the upgrade.) Some Avro values have JSON encodings that aren't technically valid JSON top-level values, since they're just bare scalars, but the new Avro function works with these just fine. The test_avro_data test case has been updated to verify the JSON encodings for each of the Avro schema types it tests.