Figure out a better way for matching the current state about robot

[matthewp]

I think the string way is probably fine for 1.0, and then figure out something better after.

[matthewp]

Tricky part of the above idea is how you match against child machines. For example:

const child = createMachine({
  one: state(transition('next', 'two')),
  two: state()
});

const machine = createMachine({
  nested: invoke(child, transition('done', 'next')),
  next: state()
});

How can you match nested.one in this case?