don't raise error when edit fails.  this was probably errorously committed
deprecate TCP receiver

* The one-line format is too restricting.
* HTTP can scale to sufficiently high throughput (and if it doesn't
we'll figure something out)
* it's too tightly coupled with sqlite3 (which is partly due to
  the sqlite backend expecting sqlite error handling to be
  done externally)
remove SCHEMA-CHANGES.  no-one is still using the old schema