Merge pull request #57 in ASAPO/asapo from bugfix_subset-can-be-added-twice to develop

common/cpp/src/database/mongodb_client.cpp

common/cpp/src/database/mongodb_client.h

tests/automatic/mongo_db/CMakeLists.txt

tests/automatic/mongo_db/insert_dataset/CMakeLists.txt

tests/automatic/mongo_db/insert_dataset/cleanup_linux.sh

tests/automatic/mongo_db/insert_dataset/cleanup_windows.bat

...omatic/mongo_db/insert_dataset/insert_dataset_mongodb.cpp