added reply delay parameter to testerhead-cpp
Added statistics collection for the commands of queue app. New event
"stats" dumps counts and moving averages for push/pop and ack/fail.
Clean a bit queue-getter driver's logic for data requesting and processing.
Should be more predictable and straightforward. Also fixed data
requesting wild spin when driver starts on queue that already had data in it.
Fixed data_pointer comparator used in queue-getter driver for storing scopes.
The old one compared actual bytes and size of the data and thus wasn't able
to distinguish different events with exactly the same data, and that
caused segfaults. New one compares just memory pointers to the data (which
is quicker) utilising the knowledge that portions comes with and belongs
to different inbound events.