Add user token authentication

[tenuki]

I've just added user_token "authentication".

Can't figure out how to add a test for it, but you can use this for testing:

__author__ = 'aweil'
import os
import unittest
import discogs_client

class UserTokenTest(unittest.TestCase):
    def setUp(self):
        with open(os.path.expanduser('~/.discogs_user_token'), 'rb') as f:
            self.discosgs_token = f.read().strip()

    def test_search(self):
        d = discogs_client.Client('TenukiWebApp1/0.1', user_token=self.discosgs_token)
        query_releases = d.search('Bit Shifter', type='artist')[0].releases[1].versions[0].labels[0].releases
        self.assertTrue( len(query_releases)>0)

if __name__ == '__main__':
    unittest.main()

Please let me know when/where to add documentation when available and if you want I to documentate it in the readme.

[tenuki]

Also, I'm using in the test my registered user agent, please let me know if there is a default for this matter or if we should use an approach like the one for the user_token..

[coveralls]

Coverage decreased (-0.08%) to 84.85% when pulling 81b5f0b on tenuki:auth-user_token into 91974be on discogs:master.

[rodneykeeling]

Code looks good to me. Neat feature to have! Please update the README file in the Authorization section that reflects this update.

[tenuki]

README updated, please take a look, english is not my native languaje..

[tenuki]

Changes done. Thanks!

[coveralls]

Coverage decreased (-0.08%) to 84.85% when pulling 5af4bbe on tenuki:auth-user_token into 91974be on discogs:master.

[coveralls]

Coverage decreased (-0.08%) to 84.85% when pulling 3eca781 on tenuki:auth-user_token into 91974be on discogs:master.

[coveralls]

Coverage decreased (-0.08%) to 84.85% when pulling 3eca781 on tenuki:auth-user_token into 91974be on discogs:master.

[rodneykeeling]

Thanks! Looks good to me. 👍

Do you have a Discogs username? This is a feature I'd like to announce in the Discogs API forum, so if you'd like a shout-out/credit, please let me know!

[tenuki]

Thanks you you. My discogs username: tenuki. Thanks.