* Add @addtogroup tags to various classes, to try and group conceptually-related classes together.
* Add brief descriptions to various Special pages, thanks to Phil Boswell.
* Moving some docs to be right above the classes they represent, so that they are picked up.
* Convert "$dbw =& wfGetDB( DB_MASTER );" --> "$dbw = wfGetDB( DB_MASTER );"
* convert "$skin =& $wgUser->getSkin();" --> "$skin = $wgUser->getSkin();"
For the time being have not changed the function definitions of wfGetDB() or User::getSkin() [i.e. they are still both return-by-ref], so as to ensure the interface does not change for extensions [some of which may still be trying to run on PHP4 environments]. However presumably at some point this can be changed too.
Also includes tiny tweak to newlines in parserTests - will show 1 rather than 2 newlines between the "Reading tests from" strings when in quiet mode.
Three reasons for this:
1) It's better for analysis tools [which want explicit variable declaration]
2) It's easier for a human to read, as it's completely explicit where the variables came from [which is something you don't get with extract() ]
3) It makes it easier to find everywhere where a variable is used with search/grep [which you can't currently do with $tbl_page variables from things like: "extract($db->tableNames( 'page', 'revision'), EXTR_PREFIX_ALL, 'tbl');"].
Otherwise, from a functionality/efficiency perspective the two forms should be identical.
By doing this have been able run static analysis over the usages of these variables, thus eliminating 5 unneeded table names from calls, plus removing 3 unused calls entirely, and it just feels subjectively slightly nicer to me.
