[TASK] Upgrade CodeMirror to v.4.5

Change-Id: Ice56e7b9b5eeccc63fac2f8852955f11fd62d97b
Reviewed-on: http://review.typo3.org/32765
Reviewed-by: Xavier Perseguers <xavier@typo3.org>
Tested-by: Xavier Perseguers <xavier@typo3.org>