Welcome to the 0.9.1 branch.
Cleaning up some whitespaces.
Use fd instead of /dev/std{out,err}

Writing to std{out,err} is done by writing to fd 1 or 2, not by writing to
/dev/std{out,err}. That's not the same.

This will fix the

	/dev/stderr: Permission denied

problem, when running this script using 'su' for example, because
/dev/stderr is a symlink to /proc/self/fd/2 on most Linux distributions
which is a symlink to /dev/{pts,tty} which isn't owned by the user who run
this script.

Again, /dev/std{in,out,err} is not the same like "stdin", "stdout" or
"stderr"!
Enabling interpretation of backslash escapes in print_verbose()

Not sure why it wasn't enabled. But we use it in print_error() and I
don't see a reason why we shouldn't activate it in print_verbose(), too.
The output file input validation didn't fail, when the output file directory didn't exist

We only checked if the output file directory was writable, but only when the
output file directory exists.

Now we will check if the output file directory exists *and* if it is also
writable. If not, we will print an appropriate error message.
Version bump for 0.9.1 release.