plog-distro: consistent logging with logback

At this point looks like log4j has a rather inconsistent behaviour.

Looks like we can send everything through logback, which pretty much rocks.

@andykram should be happy.
upshot: multiple improvments

* Stats around broken MessagePack
* The SQL printer is still not great, but better (working on tests)
* Synchronize and reuse objects, at least for now