Add strictSSL option that is passed to Request.

This should close assaf/zombie#548. However, there is currently a bug in [request](https://github.com/mikeal/request) 2.27.0 with node 0.10 so `strictSSL` does not work. See mikeal/request#418. There's a work-around referenced in [this comment](https://github.com/mikeal/request/issues/418#issuecomment-25158401).