Fix stripped double quotes

[GeoffreyFrogeye]

If you are calling a program with some double quotes " within arguments, those get stripped.

Example:

$ /usr/bin/ls -l --time-style=+"%d.%m.%Y %H:%M"
total 0
-rw-r--r-- 1 geoffrey users 0 18.05.2015 20:33 bar
$ ls -l --time-style=+"%d.%m.%Y %H:%M"
ls: cannot access %H:%M: No such file or directory
ls: cannot access %H:%M: No such file or directory
$ ls -l --time-style=+"%d.%m.%Y %H:%M" .
ls: cannot access %H:%M: No such file or directory
ls: cannot access %H:%M: No such file or directory
.:
total 0
-rw-r--r-- 1 geoffrey users 0 18.05.2015 bar

This PR fixes this behaviour.