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/Util/testsuite/src/Driver.cpp

@@ -0,0 +1,17 @@
+//
+// Driver.cpp
+//
+// Console-based test driver for Poco Util.
+//
+// Copyright (c) 2004-2006, Applied Informatics Software Engineering GmbH.
+// and Contributors.
+//
+// SPDX-License-Identifier:	BSL-1.0
+//
+
+
+#include "CppUnit/TestRunner.h"
+#include "UtilTestSuite.h"
+
+
+CppUnitMain(UtilTestSuite)