Don't try to poll stdio again on `run.complete` (fixes #28)

In a misguided effort to allow a single spooky bootstrap instance service
multiple sessions, we reentered the polling loop in the stdio server.
Unfortunately, we did this on the `run.complete` event, which can fire multiple
times, if a script calls `start` and then `run` more than once. When the first
of these fired, the stdio server set a timeout to reenter the loop, which
promptly blocked waiting for stdin data that may never come.

We now do not attempt to poll stdin again after the initial run.
Document known transport issues and bump version