If a port is not specified, pick random free port.
Close http server on stream end.
Make output a stream rather than console.x directly.

Closes #1.
Add executable.

Closes #2.
Prevent auto-closing of browser on cmdline.

Keep open with --open.

Maybe should consider auto-closing for API usage too.

Closes #3.
Remove unsupported console functions. Add missing 'debug'.

Little point having them if they don't behave.
Related #4.
Support console.x printf-style formatting.

TODO: Deal with %o vs %j.

Related #4.
Log errors + stack trace.

Should maybe consider printing some context from bundle since it's
transient.

Closes #5.
Update package.json with test script.
Add missing package.json dependencies.

Stupid.
Ensure missing deps don't happen again.

Related ef8fcc4.