* Added support for configuration of an arbitrary number of commons-style file repositories.
* Split Image.php into filerepo/File.php and filerepo/LocalFile.php
* Renamed Image::getImagePath() to File::getPath()
* Added initial support for timestamp-based file fetching (OldLocalFile), to be expanded upon by aaron.
* Changed the interface for Image/File object creation: use wfFindFile() or wfLocalFile() depending on semantics
* ImageGallery::add() now accepts a title object as the first parameter
* Moved file handling operations on upload from SpecialUpload to File
* Removed path-related functions from ImageFunctions.php. Removed static path accessors from File.
* Added a Content-Disposition header to thumb.php output
* Improved thumb.php error handling
* Updated the unit test suite to kind of partially work with modern computers. RunTests.php doesn't work just yet. Fixed an actual regression that the test suite detected -- moved some defines to Defines.php where they will be loaded consistently.
Cleaned up the new URL parsing code a bit, now able to recognize both $wgActionPaths and $wgVariantArticlePath and interpolate those variables.
Moved that bit into WebRequest::interpolateTitle() function which is called after $wgContLang stub object is created, so it can be used to get the variant list.
I'm not totally happy with all this code, but it works. The variant bits generally creep me out.
Caches for wikis with table prefixes will be lost on upgrade, caches for wikis without table prefixes will be preserved. Custom cache keys in extensions can be migrated at leisure. Extensions which write to core cache keys should be migrated ASAP, as I have done with Special:Makesysop.
* Made lines from initialiseMessages() appear as list items during installation
* Moved the bulk of the localisation data from the Language*.php files to the Messages*.php files. Deleted most of the Languages*.php files.
* Introduced "stub global" framework to provide deferred initialisation of core modules.
* Removed placeholder values for $wgTitle and $wgArticle, these variables will now be null during the initialisation process, until they are set by index.php or another entry point.
* Added DBA cache type, for BDB-style caches.
* Removed custom date format functions, replacing them with a format string in the style of PHP's date(). Used string identifiers instead of integer identifiers, in both the language files and user preferences. Migration should be transparent in most cases.
* Simplified the initialisation API for LoadBalancer objects.
* Removed the broken altencoding feature.
* Moved default user options and toggles from Language to User. Language objects are still able to define default preference overrides and extra user toggles, via a slightly different interface.
* Don't include the date option in the parser cache rendering hash unless $wgUseDynamicDates is enabled.
* Merged LanguageUtf8 with Language. Removed LanguageUtf8.php.
* Removed inclusion of language files from the bottom of Language.php. This is now consistently done from Language::factory().
* Add the name of the executing maintenance script to the debug log. Start the profiler during maintenance scripts.
* Added "serialized" directory, for storing precompiled data in serialized form.
* Made autoloader work for unserialize()
* Made XmlFunctions.php and HttpFunctions.php autoloadable modules, via Http:: and Xml::
* Made Image class autoloadable, global functions moved to ImageFunctions.php where they can be loaded on every invocation.
* Removed some unnecessary require_once() calls
* Deferred $wgValidSkinNames initialisation
* Fixed a couple of silly construct/initialise splits. My idea from C++ experience, bad practice in PHP.
* Deferred skin initialisation in ParserOptions
* Removed $wgMwRedir during an attempt to make MagicWord autoloadable. Didn't complete that, but removing the global is still the right direction.
* remove require_once() throughout whole code, yet left in few places
* move global functions in HttpUtils, ProxyTools, Credits to class methods
* php5 only: __autoload() now used, combined with class->file map and require()
* move initialization of $wgValidSkinNames to Skin::getSkinNames()
* few more changes that will surely break stuff.
