PeerState.java: remove _retransmitter

[jogger]

Maintaining that field is pure code bloat as it simply duplicates what we have in the state pushcount. Also does not work if we want multiple retransmissions.

[zzz]

Seems to be two uses now, not convinced of "pure code bloat', please explain.

1) Is a message being retransmitted now? in locked_shouldSend(), maybe could be replaced by a boolean
2) What's the next send time, in getNextDelay(), uses the _retransmitter.getNextSendTime(), i don't see how to get rid of that. Have a proposal?

required for #2649

[jogger]

If we have multiple retransmissions, we would record those. Code (including fast retransmission for which I still need to open a ticket) for 1) could be

        int pc = state.getPushCount();
        // send fresh messages if retransmissions below limit
        // retransmit first time if retransmissions below limit AND (fast retransmit OR time due)
        // send retransmitters always if time due
        if (_retranscount < _retransmax && (pc == 0 ||
            pc == 1 && (state.getStartedOn() < _lastSendFullyTime || state.getNextSendTime() <= now))
            || pc > 1 && state.getNextSendTime() <= now) {

As noted in #2412 I would use a getNextSendTime(), suggesting this for 2):

                for (OutboundMessageState state : _outboundMessages)
                    if (_retranscount < _retransmax || state.getPushCount() > 1)
                        _nextSendTime = Math.min(_nextSendTime, state.getNextSendTime());