[BUGFIX] Fix Composer autoload for ZendPdf

And cleanup some PHP comments.

Change-Id: Ica57717c5752b9671c6eafe3a372f3c370ec1560
Releases: 2.1
Resolves: #62203
Reviewed-on: http://review.typo3.org/33299
Reviewed-by: Fabien Udriot <fabien.udriot@ecodev.ch>
Tested-by: Fabien Udriot <fabien.udriot@ecodev.ch>