IPK-Package tools for use under cygwin

ipk-listfiles.sh:
	prints contents of given .ipk files to stdout (suitable for
	generating "Packages.filelist")
ipk-mkPackages.sh:
	prints control data of all given .ipk files to stdout (suitable for
	generating "Packages")
ipk-pack:
	create (old-style) ipk from given directory structure and filename
ipk-unpack:
	extract given .ipk file, creating firectory structure suitable for
	"ipk-pack"