Added private permission and clean up codes, solved potential race condition in realtime.js

lib/note.js

@@ -12,7 +12,7 @@ var db = require("./db.js");
 var logger = require("./logger.js");
 
 //permission types
-permissionTypes = ["freely", "editable", "locked"];
+permissionTypes = ["freely", "editable", "locked", "private"];
 
 // create a note model
 var model = mongoose.model('note', {
@@ -126,7 +126,11 @@ function findNote(id, callback) {
     });
 }
 
-function newNote(id, permission, callback) {
+function newNote(id, owner, callback) {
+    var permission = "freely";
+    if (owner && owner != "null") {
+        permission = "editable";
+    }
     var note = new model({
         id: id,
         permission: permission,