implemented sub_client; simplified column_client based on sub_client; remove unneeded code; added zmq subscription validation
major simplification in config_client and log_record_client by using sub_client
remove temp log output
removing unneeded file
make sure endpoint_server reports sensible endpoint details even if bound to ephemeral address
Merge pull request #13 from starschema/to-review-2014-09-09

implementd sub_client and simplified log_record_client and config_client based on that