Merge branch 'f-insert' into f-multi-retrieve

include/caosdb/entity.h

include/caosdb/exceptions.h

src/caosdb/configuration.cpp

src/caosdb/entity.cpp

test/test_configuration.cpp

test/test_connection.cpp

test/test_entity.cpp

test/test_protobuf.cpp

test/test_transaction.cpp

test/test_utility.cpp