Made the pagination options extraction work for any params

The previous code used a whitelist approach to including params, but
that does not work with facebook's new paging param 'after'. It also
excludes parameters like 'include_deleted' and 'include_completed'.

This implementation excludes the only paramater that we don't want to
circulation, access_token, since that's provided by fb_graph.
Correctly unescape and parse params for paging parameters
Merge pull request #318 from kemper/master

Fix pagination of the fb_graph gem