[ fixed ] CID 22705: Resource leak (RESOURCE_LEAK)

(test_unixml): [ fixed ] CID 22871 (#1 of 1): Unchecked return value (CHECKED_RETURN)

заодно исключил -Wctor-dtor-privacy

[fixed]: Uninitialized variables  (UNINIT)
[fixed]: Error handling issues  (UNCAUGHT_EXCEPT)
[fixed]: Control flow issues  (NO_EFFECT)
[fixed]: Uninitialized scalar variable (UNINIT)

PostgreSQLInterface: [ fixed ] error: ambiguous overload for ‘operator[]’ (operand types are ‘pqxx::result::const_iterator’ and ‘size_t {aka long unsigned int}’)

-Werror=overflow --> -Woverflow

(убрал сравнение timeout_t и std::chrono::milliseconds).