Keep namespace and timestamp metadata in a separate Elasticsearch index.
Yield both document and meta-document actions in the same generator for bulk_upsert into Elasticsearch.
Remove redundant _id in meta document for regular upsert using the Elastic DocManager.
Merge branch 'master' into 2.0-dev
prevent data loss when collection_dump=False

Conflicts:
	mongo_connector/oplog_manager.py
allow gridfs files to be text searchable
replicate commands
code review fix
Merge branch '2.0-dev' into config

Conflicts:
	mongo_connector/compat.py
	mongo_connector/connector.py
	mongo_connector/oplog_manager.py
	tests/test_oplog_manager_sharded.py
merge fixes