Merge pull request #34 from gilbertw1/master

Added oauth support for pubsubhubub endpoint
Add poll-interval to metadata. (From "X-Poll-Interval" events header.)
Merge pull request #35 from tjg/poll-interval

Add poll-interval to metadata. (From "X-Poll-Interval" events header.)
added create-auth and valid-auth? oauth functions

- create new oauth auth tokens via create-auth
- check existing auth token validity with valid-auth?
- added docstrings for oauth fns
Merge pull request #37 from JeffreyPalmer/master

added create-auth and valid-auth? oauth functions