Fix issue #159

[dpetukhov]

1. Request freezes when remote server send headers and stops.
2. Timeout not sets after redirecting request.
   https://github.com/mikeal/request/blob/master/main.js#L361 - on this line self.timeoutTimer stay assigned after redirect
   https://github.com/mikeal/request/blob/master/main.js#L487 - this line failed after redirect because self.timeoutTimer has value

Please tell me if you have additional requirements for accept this patch. Docs update, additional test, etc.

Regards,
Dmitry

[mikeal]

only set the additional socketTimeout if the timeout option is set, otherwise it should use the default socket timeout which should propagate (as of 0.6.0) to the request object and we'll already handle it.

also, test to make sure that aborting the request doesn't already cause an error. if it does then we'll end up emitting double-errors.

[dpetukhov]

This block inside if (self.timeout) and socket timeout will be applied only with current setTimeout mechanism.

About double error: I will check it.

[mikeal]

Great, after you check on the double error comment and I'll merge.