OAuth1 provider revamp. Fix #95.

A large refactor of the OAuth 1 provider. Breaking it up into 4 endpoints and aligning it much closer to OAuth 2 from an API point of view. Furthermore response and token creation has been added to make it much smoother to implement. Response format which is unspecified in the spec has been extrapolated from the examples given or back ported from the OAuth 2 equivalents. 

The new endpoints are

RequestTokenEndpoint to handle the creation of request tokens.
AuthorizationEndpoint to help in creation and validation of authorization requests, forms and responses.
AccessTokenEndpoint to handle the creation of access tokens.
ResourceEndpoint to verify access tokens.

The new documentation should be available at http://oauthlib.readthedocs.org/en/latest/oauth1/server.html after merge.

There are still a few small things remaining before release, mainly more test scenarios and docs additions/fixes.