Add security notice for encryption

Author: Rotzbua

examples/js/password.js

@@ -1,4 +1,7 @@
 var doc = new jsPDF({
+    // jsPDF supports encryption of PDF version 1.3.
+    // Version 1.3 just uses RC4 40-bit which is kown to be weak and is NOT state of the art.
+    // Keep in mind that it is just a minimal protection.
     encryption: {
         userPassword: "user",
         ownerPassword: "owner",