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/SingletonHolder.h

@@ -0,0 +1,77 @@
+//
+// SingletonHolder.h
+//
+// Library: Foundation
+// Package: Core
+// Module:  SingletonHolder
+//
+// Definition of the SingletonHolder template.
+//
+// Copyright (c) 2004-2006, Applied Informatics Software Engineering GmbH.
+// and Contributors.
+//
+// SPDX-License-Identifier:	BSL-1.0
+//
+
+
+#ifndef Foundation_SingletonHolder_INCLUDED
+#define Foundation_SingletonHolder_INCLUDED
+
+
+#include "Poco/Foundation.h"
+#include "Poco/Mutex.h"
+
+
+namespace Poco {
+
+
+template <class S>
+class SingletonHolder
+	/// This is a helper template class for managing
+	/// singleton objects allocated on the heap.
+	/// The class ensures proper deletion (including
+	/// calling of the destructor) of singleton objects
+	/// when the application that created them terminates.
+{
+public:
+	SingletonHolder():
+		_pS(0)
+		/// Creates the SingletonHolder.
+	{
+	}
+	
+	~SingletonHolder()
+		/// Destroys the SingletonHolder and the singleton
+		/// object that it holds.
+	{
+		delete _pS;
+	}
+	
+	S* get()
+		/// Returns a pointer to the singleton object
+		/// hold by the SingletonHolder. The first call
+		/// to get will create the singleton.
+	{
+		FastMutex::ScopedLock lock(_m);
+		if (!_pS) _pS = new S;
+		return _pS;
+	}
+	
+	void reset()
+		/// Deletes the singleton object.
+	{
+		FastMutex::ScopedLock lock(_m);
+		delete _pS;
+		_pS = 0;
+	}
+	
+private:
+	S* _pS;
+	FastMutex _m;
+};
+
+
+} // namespace Poco
+
+
+#endif // Foundation_SingletonHolder_INCLUDED