change signature of set_lastread_marker

CHANGELOG.md

consumer/api/cpp/include/asapo/consumer/consumer.h

consumer/api/cpp/src/consumer_impl.cpp

consumer/api/cpp/src/consumer_impl.h

consumer/api/cpp/unittests/test_consumer_impl.cpp

consumer/api/python/asapo_consumer.pxd

consumer/api/python/asapo_consumer.pyx.in

tests/automatic/consumer/consumer_api/consumer_api.cpp

tests/automatic/consumer/consumer_api_python/consumer_api.py