[BUGFIX] CSS concatenation needs to care about media types

Previously only files with media="all" have been concatenated but there
is no reason why not the others should be concatenated too.
The forceOnTop option now works for each media type.

Change-Id: Ie29e011f94d36d73b946920965a95388e46d544b
Fixes: #33137
Releases: master
Reviewed-on: http://review.typo3.org/19398


Reviewed-by: Jigal van Hemert <jigal.van.hemert@typo3.org>
Tested-by: Jigal van Hemert <jigal.van.hemert@typo3.org>