Move nut-score into website/sandbox

Also move some .gitignore entries from the top-level .gitignore into a
subdirectory .gitignore.

website/sandbox/nut-score/watcher.js

@@ -0,0 +1,39 @@
+// This is our simple, robust watcher. It hooks into the BuckleScript build
+// system to listen for build events.
+// See package.json's `start` script and `./node_modules/.bin/bsb --help`
+
+// Btw, if you change this file and reload the page, your browser cache
+// _might_ not pick up the new version. If you're in Chrome, do Force Reload.
+
+var websocketReloader;
+var LAST_SUCCESS_BUILD_STAMP = localStorage.getItem('LAST_SUCCESS_BUILD_STAMP') || 0;
+// package.json's `start` script's `bsb -ws _` means it'll pipe build events
+// through a websocket connection to a default port of 9999. This is
+// configurable, e.g. `-ws 5000`
+var webSocketPort = 9999;
+
+function setUpWebSocket() {
+  if (websocketReloader == null || websocketReloader.readyState !== 1) {
+    try {
+      websocketReloader = new WebSocket(`ws://${window.location.hostname}:${webSocketPort}`);
+      websocketReloader.onmessage = (message) => {
+        var newData = JSON.parse(message.data).LAST_SUCCESS_BUILD_STAMP;
+        if (newData > LAST_SUCCESS_BUILD_STAMP) {
+          LAST_SUCCESS_BUILD_STAMP = newData;
+          localStorage.setItem('LAST_SUCCESS_BUILD_STAMP', LAST_SUCCESS_BUILD_STAMP);
+          // Refresh the page! This will naturally re-run everything,
+          // including our moduleserve which will re-resolve all the modules.
+          // No stable build!
+          location.reload(true);
+        }
+
+      }
+    } catch (exn) {
+      console.error("The watcher tried to connect to web socket, but failed. Here's the message:");
+      console.error(exn);
+    }
+  }
+};
+
+setUpWebSocket();
+setInterval(setUpWebSocket, 2000);