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/XML/Makefile

@@ -0,0 +1,37 @@
+#
+# Makefile
+#
+# Makefile for Poco XML
+#
+
+include $(POCO_BASE)/build/rules/global
+
+COMMONFLAGS += -DXML_NS -DXML_DTD -DHAVE_EXPAT_CONFIG_H -DEXPAT_POCO
+
+objects = AbstractContainerNode AbstractNode Attr AttrMap Attributes \
+	AttributesImpl CDATASection CharacterData ChildNodesList Comment \
+	ContentHandler DOMBuilder DOMException DOMImplementation DOMObject \
+	DOMParser DOMSerializer DOMWriter DTDHandler DTDMap DeclHandler \
+	DefaultHandler Document DocumentEvent DocumentFragment DocumentType \
+	Element ElementsByTagNameList Entity EntityReference EntityResolver \
+	EntityResolverImpl ErrorHandler Event EventDispatcher EventException \
+	EventListener EventTarget InputSource LexicalHandler Locator LocatorImpl \
+	MutationEvent Name NamePool NamedNodeMap NamespaceStrategy \
+	NamespaceSupport NodeAppender Node NodeFilter NodeIterator NodeList Notation \
+	ParserEngine ProcessingInstruction QName SAXException SAXParser Text \
+	TreeWalker WhitespaceFilter XMLException XMLFilter XMLFilterImpl XMLReader \
+	XMLString XMLWriter XMLStreamParser XMLStreamParserException ValueTraits
+
+expat_objects = xmlparse xmlrole xmltok
+
+ifdef POCO_UNBUNDLED
+	SYSLIBS += -lexpat
+else
+	objects += $(expat_objects)
+endif
+
+target         = PocoXML
+target_version = $(LIBVERSION)
+target_libs    = PocoFoundation
+
+include $(POCO_BASE)/build/rules/lib