Add support for disqus

[seeeturtle]

[seeeturtle]

@manu-chroma, it seems disqus refuse user-agent of requests. I'll merge it after the PR that uses Session is merged.

[seeeturtle]

@manu-chroma , It seems User-Agent isn't the only one to get the real content from disqus...

And I can't understand why medium test fails.

[manu-chroma]

oh man, this is disappointing

[manu-chroma]

i think our safe bet is to drop medium avatar support to be honest.

it doesn't seem worth so much effort

[seeeturtle]

@manu-chroma , yeah, medium is too unpredictable... we should support medium avatar if there is way to get avatar url constantly...

btw, I think we should split the get_avatar_test to

1. no image found
2. returns different url.(the requests should be sent more than 2)

[seeeturtle]

I think the basic solution is to use api to provide constant result...(if we can)

[seeeturtle]

:thinking: I think I saw wrong thing. There's no error from medium. It's working well.

But still it's true that the basic solution is using api.