Return the request object in call

I had a need to setup a timeout on the request for some hanging SQS calls.

You can now setup code like this:
```
  req = sqs.call "GetQueueAttributes", options, (err, result) ->
    ...

  req.on "error", ->
    # handle error
  
  # setup the timeout  
  req.on "socket", (s) ->
    s.setTimeout 100
    s.on "timeout", -> do req.abort
```


Or, if you would like, I can change it up to include a timeout property in the options object. (If returning the request scares you :smile:)