Incompatible Changes affecting Serdes and UDFS

[Brock Noland]

Hi,

Hive 0.12 made some incompatible changes which impacts Serdes and it
appears 0.13 makes more incompatible changes. I created HIVE-6043 to track
this, if you know of any more changes than what is described there, please
do add them.

Thanks!
Brock