client/posts: wrap with big progress

fixes #114

client/js/util/progress.js

@@ -0,0 +1,24 @@
+const nprogress = require('nprogress');
+
+let nesting = 0;
+
+function start() {
+    if (!nesting) {
+        nprogress.start();
+    }
+    nesting++;
+}
+
+function done() {
+    nesting--;
+    if (nesting > 0) {
+        nprogress.inc();
+    } else {
+        nprogress.done();
+    }
+}
+
+module.exports = {
+    start: start,
+    done:  done,
+};