Enum support

src/AttributeName.cpp

src/AttributeName.hpp

src/AttributeTraits.cpp

src/AttributeTraits.hpp

src/ColumnCache.hpp

src/ConnectionBase.hpp

src/DbConnection.cpp

src/DbConnection.hpp

src/HdbppTimescaleDb.cpp

src/HdbppTimescaleDbApi.cpp

src/HdbppTimescaleDbApi.hpp

src/HdbppTxBase.hpp

src/HdbppTxDataEvent.hpp

src/HdbppTxDataEventBase.hpp

src/HdbppTxDataEventError.hpp

src/HdbppTxFactory.hpp

src/HdbppTxHistoryEvent.hpp

src/HdbppTxNewAttribute.hpp

src/HdbppTxParameterEvent.hpp

src/HdbppTxUpdateTtl.hpp