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/samples/LineEndingConverter/src/LineEndingConverter.cpp

@@ -0,0 +1,70 @@
+//
+// LineEndingConverter.cpp
+//
+// This sample demonstrates the line ending conversion from unix (LF) to windows (CRLF)
+// and vice-versa.
+//
+// Copyright (c) 2004-2006, Applied Informatics Software Engineering GmbH.
+// and Contributors.
+//
+// SPDX-License-Identifier:	BSL-1.0
+//
+
+
+#include "Poco/LineEndingConverter.h"
+#include "Poco/FileStream.h"
+#include "Poco/StreamCopier.h"
+#include "Poco/String.h"
+#include <sstream>
+#include <iostream>
+
+
+using Poco::InputLineEndingConverter;
+using Poco::LineEnding;
+using Poco::StreamCopier;
+using Poco::FileInputStream;
+using Poco::FileOutputStream;
+using Poco::icompare;
+
+
+inline void dosToUnix(std::istream& input, std::ostream& output)
+{
+	InputLineEndingConverter conv(input, LineEnding::NEWLINE_LF);
+	StreamCopier::copyStream(conv, output);
+}
+
+
+inline void unixToDos(std::istream& input, std::ostream& output)
+{
+	InputLineEndingConverter conv(input, LineEnding::NEWLINE_CRLF);
+	StreamCopier::copyStream(conv, output);
+}
+
+
+inline int usage()
+{
+	std::cout << "Usage: LineEndingConverter {u2d | d2u} filename" << std::endl;
+	return -1;
+}
+
+
+int main(int argc, char** argv)
+{
+	if (argc < 3) return usage();
+	if (strlen(argv[1]) != 3) return usage();
+
+	std::string conv(argv[1]);
+
+	FileInputStream fis(argv[2]);
+	std::stringstream ss;
+	StreamCopier::copyStream(fis, ss);
+	fis.close();
+
+	FileOutputStream fos(argv[2]);
+	if (0 == icompare(conv, "u2d")) unixToDos(ss, fos);
+	else if (0 == icompare(conv, "d2u")) dosToUnix(ss, fos);
+	else return usage();
+	fos.flush();
+
+	return 0;
+}