Removed encodeURIComponent wrapper on options.callback in src/auth/request.js

[learntoswim]

Tested this in reference to issue #48.

Seems to be working ok.

[Pomax]

Are you able to verify this also works if no callback URL is used?

[learntoswim]

Not supplying a callback property in options:

var options = {
    api_key: api_key
    secret: secret
};

Flickr.authenticate(options, function (err, flickr) {
    // Stuff
});

Works as expected:

URL: https://www.flickr.com/services/oauth/authorize.gne
&
prompt: oauth_verifier:  

[Pomax]

cool. let's merge this in =)

And thank you for helping improve the package!