The spriteGenerator has features to generate GIF variants (and according CSS) as a fallback for IE6.
Remove it as it is not used anymore (due to #M17805).

Resolves #M17808
Depends #M17805

Change-Id: I6fae8845d4c2ecae3ad56aa8c143dd2e1d76a8b3
Reviewed-on: http://review.typo3.org/952


Reviewed-by: Stefan Galinski <stefan.galinski@gmail.com>
Reviewed-by: Philipp Gampe <forge.typo3.org@philippgampe.info>
Reviewed-by: Andreas Wolf <andreas.wolf@ikt-werk.de>
Tested-by: Andreas Wolf <andreas.wolf@ikt-werk.de>