Revert "An experiment: using datagrams to provide framing"

This reverts commit 58ad21ac4e4f81fd3102822d88a4eec67133abb3.

Wow, datagrams were slow.  They cost nearly twice as much as writes and
reads to plain pipes, even despite the fact that such operations require
buffering to work.

Conflicts:
	assay/worker.py