iptables-restore: Support for extra debug output

iptables-restore: Support for extra debug output

Treat --verbose just like iptables itself, increasing debug level with
number of invocations.

To propagate the level into do_command() callback, insert virtual '-v'
flags into rule lines.

The only downside of this is that simple verbose output is changed and
now also prints the rules as they are added - which would be useful if
the lines contained the chain they apply to.

Signed-off-by: Phil Sutter <phil@nwl.cc>