started delete_events
deleting based on policy_id
Merge branch 'master' into delete_schedule_event
delete_events takes list of policy ids

also, removed few unnecessary setup in tests
using params instead of expanding cql in code
values dict should not have ':'
addressed ying's comments
Merge branch 'master' into delete_schedule_event
using string.format
Merge pull request #226 from rackerlabs/delete_schedule_event

Delete scheduled events