Http Avro Serializer and tests
re-format test files
Merge branch 'master' of https://github.com/Microsoft-CISL/REEF into juwang-httpAvroSerilazer
adding negative test cases for AvroHttpSerializer
add final and rename for variables
Merge branch 'master' of https://github.com/Microsoft-CISL/REEF into juwang-httpAvroSerilazer
handle exceptions in test
Merge branch 'juwang-httpAvroSerilazer' into juwang-httpAvroSerilazerBridge
juwang-reef-bridge-HttpAvro-Serializer
Merge pull request #829 from Microsoft-CISL/juwang-httpAvroSerilazerBridge

Juwang http avro serilazer bridge. The change in the branch is merged from juwang-httpAvroSerilazer (branched from master) and juwang-reef-bridge-HttpAvro-Serializer (branched from reef-bridge). Both have been reviewed.