Add new "binary" option to support downloading binary files.

[ian-mcdowell]

The httpreq library will not properly download binary files without using the "binary" option. This change adds an option to httpntlm that gets passed through to httpreq. It's false by default.

I've verified that this works on my own installation, downloading an image from a server.

[SamDecrock]

You can just pass "binary" to the regular options object:

httpntlm.get({
    url: "https://someurl.com",
    username: 'm$',
    password: 'stinks',
    workstation: 'choose.something',
    domain: '',
    binary: true
}, function (err, res){
    if(err) return err;

    console.log(res.headers);
    console.log(res.body);
});