Fix for bug 9413 and the related Malayalam issue reported on wikitech-l.

Fix for bug 9413 and the related Malayalam issue reported on wikitech-l.
* Added $wgFixArchaicUnicode, which, if enabled, converts some deprecated Unicode sequences in Arabic and Malayalam text to their Unicode 5.1 equivalents.
* Added generateNormalizerData.php to generate the relevant data files. Added the generated data files also.
* Made most things call the new wrapper method $wgContLang->normalize() instead of UtfNormal::cleanUp(), so that Unicode normalization can be customised on a per-language basis.
* Added some generic support for conversion tables to Language so that subclasses can easily implement these kinds of transformations.