* 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.
