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/include/Poco/EventChannel.h

@@ -0,0 +1,56 @@
+//
+// EventChannel.h
+//
+// Library: Foundation
+// Package: Logging
+// Module:  EventChannel
+//
+// Definition of the EventChannel class.
+//
+// Copyright (c) 2015, Applied Informatics Software Engineering GmbH.
+// and Contributors.
+//
+// SPDX-License-Identifier:	BSL-1.0
+//
+
+
+#ifndef Foundation_EventChannel_INCLUDED
+#define Foundation_EventChannel_INCLUDED
+
+
+#include "Poco/Foundation.h"
+#include "Poco/Channel.h"
+#include "Poco/Message.h"
+#include "Poco/BasicEvent.h"
+
+
+namespace Poco {
+
+
+class Foundation_API EventChannel: public Channel
+	/// The EventChannel fires the messageLogged event for every log message
+	/// received. This can be used to hook custom log message processing into
+	/// the logging framework. 
+{
+public:
+	using Ptr = AutoPtr<EventChannel>;
+
+	Poco::BasicEvent<const Message> messageLogged;
+		/// Fired when a message is logged by calling the log() method.
+
+	EventChannel();
+		/// Creates the EventChannel.
+
+	void log(const Message& msg);
+		/// Fires the messageLogged event.
+
+protected:
+	~EventChannel();
+		/// Destroys the EventChannel.
+};
+
+
+} // namespace Poco
+
+
+#endif // Foundation_EventChannel_INCLUDED