avro

AVRO-2546: Add bzip2 and xz support to the Python3 bindings (#638)

* AVRO-2546: Add bzip2 and xz support to the Python3 bindings

* Add bzip2 and xz support to the Python3 bindings

* Add data interoperability test for these codecs
  executed between Java and Python3

* Fix the Python2 data interop test to skip the files
  which are compressed with the unsupported codecs

* Add print statements to the Python test codes so that
  developers can confirm which files are read and skipped
  during the data interop tests

* Move compression codec strings to constants