Don't have a default authentication client. Rationale: If user wants an authentication client, they would have to configure an authentication client (set user/password on it) and then set it onto the stream config. (Also to be more consistent with java stream client).
remove read_from_file from Config. Fix docs, slightly.
extract default values, per PR comment.
Update config.py
insert line break
Merge pull request #73 from caskdata/feature/streamclient-config-update

Remove default auth client, make config