Binary downloads and timeout as options

This PR adds the following options to httpntlm.js:

- `binary: true` (Default is false)
  - Download of binary URIs. httpreq offers back a buffer instead of a string. 
- `timeout: <ms>`: Adds a custom timeout (in milliseconds) to the http(s) request.
  - `err` will be `{ [Error: request timed out] code: 'TIMEOUT' }` in case that timeout is shorter than the server response. Default is 0 which waits until doomsday.

P.S: Did some jshint stuff - so there should be some extra `;` and some less `var`'s