add feedsaver-server cli tool

server/feedsaver-server.go

+package main
+
+import (
+	"flag"
+	"autistici.org/feedsaver"
+)
+
+var (
+	addr = flag.String("addr", ":5000", "TCP address to listen on")
+	storage_root = flag.String("storage_dir", "./tmp", "Root of the storage directory")
+)
+
+func main() {
+	flag.Parse()
+
+	storage := feedsaver.NewStorage(*storage_root)
+
+	feed := feedsaver.NewFeedsaver(storage)
+	feed.Run(*addr)
+}