Cleaned up tests for snappy compression
Cleaned up tests for snappy compression

Existing tests for decompression have been cleaned up a bit. Added new
test for compression functionality.

DEvil0000/libkafka-asio,tempbottle/libkafka-asio,danieljoos/libkafka-asio,DEvil0000/libkafka-asio,tempbottle/libkafka-asio,danieljoos/libkafka-asio