There are 2 distinct kinds of timeout events:
- an unresponsive node
  This is a connection-level timeout.
  This is handled by the Timeout class, triggering pings and monitoring
  incoming data to decide when remote node is considered dead.
- a "too long" processing from an otherwise responsive node
  This is a per-request timeout.
  This is handled by the HandlerSwitcher class, triggering only
  disconnections when an answer takes too long to arrive (historical
  behaviour, not so useful when exchanging with a single-threaded peer).

Previous implementation mixed both, and had shortcomings (ping would
timeout almost immediately, it was not possible to tell which message
caused a timeout).

Update tests.

git-svn-id: https://svn.erp5.org/repos/neo/trunk@2009 71dcc9de-d417-0410-9af5-da40c76e7ee4