Fixed initial oauth authetication

Upon first running scripts/figshare at the command line, I was getting
an error "ValueError: No client verifier has been set." from
oauth_requests. Referring to
http://requests-oauthlib.readthedocs.org/en/latest/oauth1_workflow.html,
I saw that some parts of the initial authentication process were missing
like getting the request token and authorization. I added them in. I
changed some of the variable names to match those in the RTD page above.
It might be worth standardizing the variable names in that function to
those in the RTD example.