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/NetSSL_OpenSSL/include/Poco/Net/InvalidCertificateHandler.h

@@ -0,0 +1,80 @@
+//
+// InvalidCertificateHandler.h
+//
+// Library: NetSSL_OpenSSL
+// Package: SSLCore
+// Module:  InvalidCertificateHandler
+//
+// Definition of the InvalidCertificateHandler class.
+//
+// Copyright (c) 2006-2009, Applied Informatics Software Engineering GmbH.
+// and Contributors.
+//
+// SPDX-License-Identifier:	BSL-1.0
+//
+
+
+#ifndef NetSSL_InvalidCertificateHandler_INCLUDED
+#define NetSSL_InvalidCertificateHandler_INCLUDED
+
+
+#include "Poco/Net/NetSSL.h"
+#include "Poco/Net/VerificationErrorArgs.h"
+
+
+namespace Poco {
+namespace Net {
+
+
+class NetSSL_API InvalidCertificateHandler
+	/// A InvalidCertificateHandler is invoked whenever an error occurs verifying the certificate. It allows the user
+	/// to inspect and accept/reject the certificate.
+	/// One can install one's own InvalidCertificateHandler by implementing this interface. Note that
+	/// in the implementation file of the subclass the following code must be present (assuming you use the namespace My_API 
+	/// and the name of your handler class is MyGuiHandler):
+	///    
+	///    #include "Poco/Net/CertificateHandlerFactory.h"
+	///    ...
+	///    POCO_REGISTER_CHFACTORY(My_API, MyGuiHandler)
+	///
+	/// One can either set the handler directly in the startup code of the main method of ones application by calling
+	///
+	///    SSLManager::instance().initialize(mypassphraseHandler, myguiHandler, mySSLContext)
+	///
+	/// or in case one uses Poco::Util::Application one can rely on an XML configuration and put the following entry
+	/// under the path openSSL.invalidCertificateHandler:
+	///    
+	///    <invalidCertificateHandler>
+	///        <name>MyGuiHandler<name>
+	///        <options>
+	///            [...] // Put optional config params for the handler here
+	///        </options>
+	///    </invalidCertificateHandler>
+	///
+	/// Note that the name of the InvalidCertificateHandler must be same as the one provided to the POCO_REGISTER_CHFACTORY macro.
+{
+public:
+	InvalidCertificateHandler(bool handleErrorsOnServerSide);
+		/// Creates the InvalidCertificateHandler.
+		/// 
+		/// Set handleErrorsOnServerSide to true if the certificate handler is used on the server side.
+		/// Automatically registers at one of the SSLManager::VerificationError events.
+
+	virtual ~InvalidCertificateHandler();
+		/// Destroys the InvalidCertificateHandler.
+
+	virtual void onInvalidCertificate(const void* pSender, VerificationErrorArgs& errorCert) = 0;
+		/// Receives the questionable certificate in parameter errorCert. If one wants to accept the
+		/// certificate, call errorCert.setIgnoreError(true).
+
+protected:
+	bool _handleErrorsOnServerSide;
+		/// Stores if the certificate handler gets invoked by the server (i.e. a client certificate is wrong)
+		/// or the client (a server certificate is wrong)
+};
+
+
+} } // namespace Poco::Net
+
+
+#endif // NetSSL_InvalidCertificateHandler_INCLUDED