[TASK] Update codemirror to recent version 0.9.4

TYPO3 4.5 already uses the codemirror library 0.9.4. It has not yet been updated for 4.6.

Change-Id: I5ada44a795d47465025fb8e7c6de1ff61f5249d9
Resolves: #28854
Releases: 4.6
Reviewed-on: http://review.typo3.org/5670
Reviewed-by: Stefan Neufeind
Tested-by: Stefan Neufeind
Reviewed-by: Xavier Perseguers
Tested-by: Xavier Perseguers