Adding some filter hooks for us to use.
Merge pull request #1 from methnen/filters

Adding some filter hooks for us to use.
A few mostly minor tweaks to oauth2 class in keyring:
- Removed (int) typing from line 84, as far as I can tell facebook doesn't say this has to be an integer and in our token store it's not.
- Removed a filter hook I'd previous added but that wasn't necessary since oauth2 is an extension of oauth1.
- Weee!
Merge pull request #2 from methnen/more-keyring-tweaks

A few mostly minor tweaks to oauth2 class in keyring:
don't int cast the var that doesn't need tp be an int