Suggestion: use a futures API rather than callbacks

So instead of writing:

```
syn.type(a, "x", function() {
syn.click(b, function() {
syn.click(c, function() {
syn.click(d)
})
})
})
```

you could write something like:

```
syn.type(a, "x").then(function() {
return syn.click(b)
}).then(function() {
return syn.click(c)
}).then(function() {
return syn.click(d)
}).done()
```

so you don't get all stuck in callback hell. I'd suggest a futures library but i don't wanna plug my stuff too much all at once ; )

Start by reviewing the callback-based syn.type and syn.click examples in the issue and the existing public API. Determine how a futures-style chain should behave, including completion through done(). Done means the event methods support the proposed chained usage without callback nesting and the existing behavior remains covered.

Written by the indexing model from the issue text.