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/Utility.h

@@ -0,0 +1,52 @@
+//
+// Utility.h
+//
+// Library: NetSSL_OpenSSL
+// Package: SSLCore
+// Module:  Utility
+//
+// Definition of the Utility class.
+//
+// Copyright (c) 2006-2009, Applied Informatics Software Engineering GmbH.
+// and Contributors.
+//
+// SPDX-License-Identifier:	BSL-1.0
+//
+
+
+#ifndef NetSSL_Utility_INCLUDED
+#define NetSSL_Utility_INCLUDED
+
+
+#include "Poco/Net/NetSSL.h"
+#include "Poco/Net/Context.h"
+
+
+namespace Poco {
+namespace Net {
+
+
+class NetSSL_API Utility
+	/// This class provides various helper functions for working
+	/// with the OpenSSL library.
+{
+public:
+	static Context::VerificationMode convertVerificationMode(const std::string& verMode);
+		/// Non-case sensitive conversion of a string to a VerificationMode enum.
+		/// If verMode is illegal an InvalidArgumentException is thrown.
+
+	static std::string convertCertificateError(long errCode);
+		/// Converts an SSL certificate handling error code into an error message.
+
+	static std::string getLastError();
+		/// Returns the last error from the error stack
+
+	static void clearErrorStack();
+		/// Clears the error stack
+};
+
+
+} } // namespace Poco::Net
+
+
+#endif // NetSSL_Utility_INCLUDED