fix output handling for subprocesses with multi-byte chars

See merge request !1

Use consecutive ids for checkpoints and include the agreementSeqNr as
one of the fields that has to be identical across checkpoints.

The concurrent log output from the concurrent connection setup can garble the output otherwise

Only accept timestamps without leading whitespace and which are large enough
to possibly be a timestamp

One simply should not close System.out ...

The expired flag of an expired timer was not properly cleared before queueing it again.

A newly created timer was always considered as running.