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.
mongo_connector.doc_managers => namespace package
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
fixes from code review
screwed up
Merge branch '2.0-dev' into commands

Conflicts:
	mongo_connector/connector.py
	mongo_connector/doc_managers/__init__.py
	mongo_connector/doc_managers/elastic_doc_manager.py
	mongo_connector/oplog_manager.py