github_54: have basic working elastic doc manager using the official python driver for elasticsearch
github_54: using custom exceptions in elastic_doc_manager & corresponding tests
github_54: removed 'pyes' requirement and added 'elasticsearch'
added 'mongo_connector.doc_managers' package back to 'packages'
github_54: using elastic "scan" search for the elastic doc manager
fixed error message
set auto_commit to False for elastic_doc_manager
github_54: finishing implentation of elastic_doc_manager with 'elasticsearch' package