connector.py by adding ConnectorException as base exception class and a 
ConnectorConnectionRefusedException raised in makeClientConnection() or 
recv(). All sockets error are wrapped in ConnectorException and special
(unknown) cases are not catched in connection.py


git-svn-id: https://svn.erp5.org/repos/neo/branches/prototype3@492 71dcc9de-d417-0410-9af5-da40c76e7ee4