Use base URL/access_token from URI if provided
Use base URL/access_token from URI if provided

Don't use self.base_url/self.access_token if they can be found in the
URI passed to request().

Also: guard against calls that omit the params/data keyword arguments.

arifgursel/rauth,litl/rauth,isouzasoares/rauth,isouzasoares/rauth,arifgursel/rauth,litl/rauth,maxcountryman/rauth,maxcountryman/rauth,arifgursel/rauth