add python functions, add tests

common/cpp/include/asapo/common/networking.h

common/cpp/src/database/mongodb_client.cpp

producer/api/cpp/src/producer_impl.cpp

producer/api/cpp/unittests/test_producer_impl.cpp

producer/api/python/asapo_producer.pxd

producer/api/python/asapo_producer.pyx.in

receiver/CMakeLists.txt

receiver/src/request_handler/request_factory.cpp

receiver/src/request_handler/request_factory.h

receiver/src/request_handler/request_handler_db_get_meta.cpp

receiver/src/request_handler/request_handler_db_get_meta.h

receiver/unittests/request_handler/test_request_factory.cpp

...ests/request_handler/test_request_handler_db_get_meta.cpp

tests/automatic/consumer/consumer_api/CMakeLists.txt

tests/automatic/mongo_db/meta/meta_mongodb.cpp

tests/automatic/producer/cpp_api/CMakeLists.txt

tests/automatic/producer/cpp_api/check_linux.sh

tests/automatic/producer/cpp_api/producer_api.cpp

tests/automatic/producer/python_api/check_linux.sh

tests/automatic/producer/python_api/check_windows.bat