Auth via header should use token

[cj]

I think the authentication via header should be like github's curl -H "Authorization: token OAUTH-TOKEN" https://api.github.com rather than what doorkeepers currently is curl -H "Authorization: OAUTH-TOKEN" https://api.github.com. Changing it will allow basic/digest auth etc....

source: http://developer.github.com/v3/

[felipeelias]

Github probably uses an extension of access token.

We already accept header authorization via Bearer token, which is defined in section 7.1. This is also compatible with the oauth2 gem (if you use the defaults).

Not sure if it makes sense to change this right now. However, access token extensibility is definitely one of the features we should add in the future.