Enabled bools, fixed strings, updated schema

db-schema/schema.sql

db-schema/schema_updated.sql

src/DbConnection.cpp

src/DbConnection.tpp

src/HdbppTxDataEvent.hpp

src/PqxxExtension.hpp

test/DbConnectionTests.cpp

test/HdbppTxDataEventTests.cpp

test/TestHelpers.cpp

test/TestHelpers.hpp

test/main.cpp