Doxygen documentation update:
* Changed alls @addtogroup to @ingroup. @addtogroup adds the comment to the group description, but doesn't add the file, class, function, ... to the group like @ingroup does. See for example http://svn.wikimedia.org/doc/group__SpecialPage.html where it's impossible to see related files, classes, ... that should belong to that group.
* Added @file to file description, it seems that it should be explicitely decalred for file descriptions, otherwise doxygen will think that the comment document the first class, variabled, function, ... that is in that file.
* Removed some empty comments
* Removed some ?>
Added following groups:
* ExternalStorage
* JobQueue
* MaintenanceLanguage
One more thing: there are still a lot of warnings when generating the doc.
* removing some unused global declarations.
* removing or commenting out or adding comments for unused local vars.
* Adding one or two local var declarations.
* Declaring $matches array passed to preg_match() / preg_match_all() as array() before using [not required, just have a slight preference for the explicitness].
* remove one or two pass-by-reference function declarations where the value is not modified.
* Adding some braces to if-else blocks.
* In Parser.php, stripstrate is now an object rather than an array as per r17820, so we no longer need ask for a reference to it (as in "$x =& $this->mStripState;"), and in fact it's probably just simpler to get rid of $x altogether.
* Moving some preg regexes from "" quoting to '' quoting to stop static analyzer whinging about bad escape sequences.
... up to "LinksUpdate.php" in the includes/ directory.
