Log process name from java management API (which includes PID)

Useful in debugging.
Move ExecutionStarting back to synchronized on work queue

It needs to be atomic with removing from the queue, which
I broke earlier.
Add a periodic log-flush timer for when server gets stuck

This may be the last thing we can do to ensure we get
logs without just flushing on every line.

With this periodic flush, if the server hangs we can
see where it's stuck, without it we just see some
arbitrary point up before it's stuck.
Print out initial configuration when executing command engine
Fix TestExecution integration test not to stick a stale server

This does suggest that we have a problem where if a task hangs
we never force-terminate the stuck sbt server, but will save
a full fix for that for another day.