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/Zip/Makefile

@@ -0,0 +1,18 @@
+#
+# Makefile
+#
+# Makefile for Poco Zip
+#
+
+include $(POCO_BASE)/build/rules/global
+
+objects = AutoDetectStream Compress Decompress ParseCallback PartialStream \
+	SkipCallback ZipArchive ZipArchiveInfo ZipDataInfo \
+	ZipFileInfo ZipLocalFileHeader ZipStream ZipUtil ZipCommon ZipException \
+	Add Delete Keep Rename Replace ZipManipulator ZipOperation
+
+target         = PocoZip
+target_version = $(LIBVERSION)
+target_libs    = PocoFoundation
+
+include $(POCO_BASE)/build/rules/lib