Connection state change indication floods DPM mailbox

Whenever a class 1 or class 3 connection is opened or closed, a connection state change indication is generated towards the host application. Despite the fact that in a real world scenario, such connections are not opened or closed in rapid succession, this case has to be considered for stress and conformance testing scenarios.

As it is done with other indications, please consider "sychronification" of the EIP_OBJECT_CONNECTION_IND for at least the opening of class 3 connections, i.e. block the further opening of the connection until the host has replied to the indication. This should be sufficient to prevent flooding of the host application, since this approach limits the maximum number of connection state change indications that can be in the round trip to the maximum number of connectons that can be opened at the device in parallel. For class 1 connections, this is less problematic, since the connection transists into the "open" state not sooner than with the first I/O datagram received by the adapter.