setting $Local:DB::NO_LOG_QUERIES true was preventing sql trace output in QueryLogger::log_query so moved it to QueryLogger to take effect on dispatcher log() command; new Utils::datetime_to_string method + test file
* move filename/filetype validation to earlier in object creation cycle, from BUILD to _build_filetype, as empty args to object causing undef value errors in _build_filetype before finally dying in BUILD block * replaced try/catch with Test::Exception throws_ok
