Welcome to the 0.9.1 branch.
Cleaning up some whitespaces.
Use fd instead of /dev/std{out,err} (Fixes #2)

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 existing ipset wasn't replaced when the new ipset was empty. (Fixes #1)

When no '*.dat' files were found, we returned from do_create_ipset_dump()
before we added the swap command. That's why the new updated (and now
empty) ipset never got in place.
v0.9.1 Release