bug in DOMElementWriter

[Jon Stevens]

Say you have an element like this:

<foo attr="&#10;" />

If you want to load that through an XMLFragment and then output it later,
the DOMElementWriter.encode() method doesn't case properly for non-printable
characters.

The quick fix for me in this case was to overload that method and add this:

                case '\n':
                    sb.append("&#10;");
                    break;

Obviously, you'd want a more complete encoding of all possible values.

jon