Merged pull requests from https://github.com/pelle/oauth-plugin/pull/132 (OAuth 2 refresh tokens should now work) and https://github.com/pelle/oauth-plugin/pull/137 (allow? will now return false when the token is not found)
Don't try and use client_application if we didn't find it (https://github.com/pelle/oauth-plugin/pull/125)
Added refresh_token accessor
Made the OAuth 2 redirect_uri param in the options hash mandatory and created a method to get it.
Made the access token refresh when necesary. It checks for the expires_in and expires_at timestamps when creating a new ConsumerToken and it gives defaults (3600 seconds, 1 hours) when none are given. It then refreshes the token and updates it in the datastore.
Added fields for expired_at and expired_in to the migration.
I forgot to persist the access token in the process of updating for OAuth 2.0, now fixed (HOW DO YOU FORGET SUCH A THING!?)
Merge pull request #139 from RubenHoms/feature/access-token-refresh

OAuth 2.0 functionality and other fixes