Decline unused offers and remove hard-coded 5 second poll for tasks
Add missing events
Switching tasks endpoint to return JSON
Merge pull request #12 from twitter/missing_events

Add missing events
use NewEncoder for json marshaling
to pointer
Merge pull request #13 from twitter/jsontasks

Switching tasks endpoint to return JSON
Merge pull request #11 from twitter/taskoffer

Decline unused offers and remove hard-coded 5 second poll for tasks