Use the file name as initial title

www/pad/main.js

@@ -372,6 +372,8 @@ define([
                 };
                 if (!initializing) {
                     hjson[3].metadata.title = document.title;
+                } else if (Cryptpad.initialName) {
+                    hjson[3].metadata.title = Cryptpad.initialName;
                 }
                 return stringify(hjson);
             };