Add oauth parameter naming possibility about oauth2

[mfpgod]

Possible solution i have made is adding the virtual method below:

protected virtual IAuthenticator GetAuthenticator(string accessToken)
{
return new ...;
}

[titarenko]

Hi,

OK, I see the issue. Could you please fork the repo, commit suggested solution and then create pull request? In this case I will then review and merge your solution into OAuth2.

Thanks for collaboration!

[titarenko]

Recently I've received patch from one of OAuth2 users with LinkedIn client implementation (using OAuth2), so it will be included into upcoming version.

[titarenko]

Scheduled for v0.9 release (please see #23).