added a -n|--namespace option to ingest
SnapshotMeta.latest should take latest based of date/store pair, not just date
SnapshotMeta.latest should take latest based of date/store pair, not just date
Take the greatest snapshot id when there are duplicate snapshots

- Added more test cases
- Added OldIdentifier arbitrary
added a regression test for ingest
Merge pull request #144 from ambiata/topic/easy-picking/add-namespace-option-to-ingest

added a -n|--namespace option to ingest
Using poacher to access Hdfs