[BUGFIX] Use double quoted strings for control chars

Instead of literal characters in single quoted strings it's better
to use doubled quoted strings for control characters to provide
better compatibility across platforms

Change-Id: Icb9722ad0e729c898d458c085f89d0fdf1f13896
Fixes: #40672
Releases: 6.0
Reviewed-on: http://review.typo3.org/14603
Reviewed-by: Felix Kopp
Tested-by: Felix Kopp
Reviewed-by: Helmut Hummel
Tested-by: Helmut Hummel