#8 Redo "Verify Language XML file" option

[Nigel Gay]

The "Verify that all necessary entries are in the Language XML file" option in the language XML editor needs a complete overhaul. While it currently spots missing entries:
1) If you start from a blank file, the XML file it produces doesn't conform to the XSD because all the mandatory descriptions don't get added in with values defaulted from the server XML.
2) It doesn't spot missing language entries for enums.
The "TestLanguageDatabase" JUnit test does a much more thorough job, so the editor option needs redoing based on that. That's not entirely straightforward since the editor option needs to operate on the in-memory copy of the XML and XSD files and uses JDom whereas the JUnit test works from reading the XML and XSD files from disk files and uses the regular Dom interface.

So I'm not going to make any attempt to solve this for 0.9.4 and perhaps not for 0.9.5 either, I need to spend the time working on the actual server+client instead of being stuck working on the editor, so just logging it as a future thing that needs to be worked on at some point.