Adds BatchID interval to TS interval
Oops bad entries.
Remove the Timestamp + Timestamp method.

Update the interval mappings with batchID -> Timestamp, update test to cover it
Add Milliseconds class, use it
Fix bug in commit
Fixes typo
Merge branch 'develop' of github.com:twitter/summingbird into feature/batch_interval_to_ts_interval
Merge pull request #443 from twitter/feature/batch_interval_to_ts_interval

Adds BatchID interval to TS interval