add go program to serve localhost with proper CORS and range support

examples/serve_localhost.go

@@ -0,0 +1,22 @@
+package main
+
+import (
+        "flag"
+        "log"
+        "net/http"
+)
+
+func main() {
+    port := flag.String("p", "7000", "port to serve on")
+    directory := flag.String("d", ".", "the directory containing PMTiles archives")
+    flag.Parse()
+
+    http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
+        w.Header().Set("Access-Control-Allow-Origin", "*")
+        w.Header().Set("Access-Control-Allow-Headers", "Range")
+        http.ServeFile(w, r, r.URL.Path[1:])
+    })
+
+    log.Printf("Serving %s on HTTP port: %s\n", *directory, *port)
+    log.Fatal(http.ListenAndServe(":"+*port, nil))
+}