Implement notification to plugins for disconnect request, connect, drop,
and close. This allows plugins to properly handle slaves and the master
server shutting down without sending messages that will get lost.
Replace current configuration mess with a trimmed down version of the
original vision of #200. Configs are collection of config groups that
have fields that can be set. These groups allow organizing the fields
as well as opertunity for plugins to add their own groups. By default
plugins have an auto generated group with the enabled field.
Hornwitser