TYPO3 Core

I'd like to propose the backport of autoloading-functionality which was added to 4.6 to be able to autoload classes that follow the extbase-namingconvetion. Together with other functionality currently proposed this might allow to use a newer Extbase-version (of course unsupported!) on the 4.5-branch. Also other extensions might make use of the new autoloading-functionality by needing to define less ext_autoload.php-entries explicitly.

Adding additional ext_autoload.php-entries to workaround this in all places is imho no real option!

During the work on this it turned out that there is not really just one commit that can be cherrypicked but that several modifications have meanwhile been done on the 4.6-branch.
Also it might be a good idea to backport the cache_phpcode as well (for 4.5: with a check added if the caching-framework is to be used!) so we don't need to "rip out" a good functionality from the autoloading where it might already be part of the backports. Leaving it out would surely have a negative performance-impact.