'SecondaryEventHandler', used in the secondary role, is now renamed as
PrimaryMasterEventHandler since a secondary is only connected to the primary. On
the other side, the primary apply the SecondaryMasterEventHandler on it's master
connections.
Factorize code in connection(Closed|Timeout)/peerBroken and avoid some checks of 
conditions that can be assume in specialized handlers.
Clean imports and remove some instance checks.


git-svn-id: https://svn.erp5.org/repos/neo/branches/prototype3@691 71dcc9de-d417-0410-9af5-da40c76e7ee4