Add some event types for the compressed event, there are:
     QUERY_COMPRESSED_EVENT,
     WRITE_ROWS_COMPRESSED_EVENT_V1,
     UPDATE_ROWS_COMPRESSED_EVENT_V1,
     DELETE_POWS_COMPRESSED_EVENT_V1,
     WRITE_ROWS_COMPRESSED_EVENT,
     UPDATE_ROWS_COMPRESSED_EVENT,
     DELETE_POWS_COMPRESSED_EVENT.
These events inheritance the uncompressed editor events. One of their constructor functions and write
function have been overridden for uncompressing and compressing. Anything but this is totally the same.

On slave, The IO thread will uncompress and convert them When it receiving the events from the master.
So the SQL and worker threads can be stay unchanged.

Now we use zlib as compress algorithm. It maybe support other algorithm in the future.