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/Net/samples/SMTPLogger/src/SMTPLogger.cpp

@@ -0,0 +1,70 @@
+//
+// Mail.cpp
+//
+// This sample demonstrates the SMTPChannel class.
+//
+// Copyright (c) 2005-2006, Applied Informatics Software Engineering GmbH.
+// and Contributors.
+//
+// SPDX-License-Identifier:	BSL-1.0
+//
+
+
+#include "Poco/Net/MailMessage.h"
+#include "Poco/Net/SMTPChannel.h"
+#include "Poco/Logger.h"
+#include "Poco/Path.h"
+#include "Poco/AutoPtr.h"
+#include "Poco/Exception.h"
+#include <iostream>
+
+
+using Poco::Net::SMTPChannel;
+using Poco::Logger;
+using Poco::Path;
+using Poco::AutoPtr;
+using Poco::Exception;
+
+
+#if defined(POCO_OS_FAMILY_UNIX)
+const std::string fileName = "${POCO_BASE}/Net/samples/SMTPLogger/res/logo.gif";
+#elif defined(POCO_OS_FAMILY_WINDOWS)
+const std::string fileName = "%POCO_BASE%/Net/samples/SMTPLogger/res/logo.gif";
+#endif
+
+
+int main(int argc, char** argv)
+{
+	if (argc != 4)
+	{
+		Path p(argv[0]);
+		std::cerr << "usage: " << p.getBaseName() << " <mailhost> <sender> <recipient>" << std::endl;
+		std::cerr << "       Send an email log entry from <sender> to <recipient>," << std::endl;
+		std::cerr << "       the SMTP server at <mailhost>." << std::endl;
+		return 1;
+	}
+	
+	std::string mailhost(argv[1]);
+	std::string sender(argv[2]);
+	std::string recipient(argv[3]);
+	std::string attachment = Path::expand(fileName);
+
+	try
+	{
+		AutoPtr<SMTPChannel> pSMTPChannel = new SMTPChannel(mailhost, sender, recipient);
+		pSMTPChannel->setProperty("attachment", attachment);
+		pSMTPChannel->setProperty("type", "image/gif");
+		pSMTPChannel->setProperty("delete", "false");
+		pSMTPChannel->setProperty("throw", "true");
+
+		Logger& logger = Logger::get("POCO Sample SMTP Logger");
+		logger.setChannel(pSMTPChannel.get());
+		logger.critical("Critical message");
+	}
+	catch (Exception& exc)
+	{
+		std::cerr << exc.displayText() << std::endl;
+		return 1;
+	}
+	return 0;
+}