Major plugin refactor and cleanup.

Switched to POCO library for unified platform/library interface.
Deprecated the external module API. It was creating more problems than solving.
Removed most built-in libraries in favor of system libraries for easier maintenance.
Cleaned and secured code with help from static analyzers.

vendor/POCO/Foundation/samples/DateTime/src/DateTime.cpp

@@ -0,0 +1,39 @@
+//
+// DateTime.cpp
+//
+// This sample demonstrates the DateTime class.
+//
+// Copyright (c) 2004-2006, Applied Informatics Software Engineering GmbH.
+// and Contributors.
+//
+// SPDX-License-Identifier:	BSL-1.0
+//
+
+
+#include "Poco/LocalDateTime.h"
+#include "Poco/DateTime.h"
+#include "Poco/DateTimeFormat.h"
+#include "Poco/DateTimeFormatter.h"
+#include "Poco/DateTimeParser.h"
+#include <iostream>
+
+
+using Poco::LocalDateTime;
+using Poco::DateTime;
+using Poco::DateTimeFormat;
+using Poco::DateTimeFormatter;
+using Poco::DateTimeParser;
+
+
+int main(int argc, char** argv)
+{
+	LocalDateTime now;
+	
+	std::string str = DateTimeFormatter::format(now, DateTimeFormat::ISO8601_FORMAT);
+	DateTime dt;
+	int tzd;
+	DateTimeParser::parse(DateTimeFormat::ISO8601_FORMAT, str, dt, tzd);
+	dt.makeUTC(tzd);
+	LocalDateTime ldt(tzd, dt);
+	return 0;
+}