Given a list of subnets, generate a list of all the other subnets
Examples:
> cat rfc1918.txt
10.0.0.0/8
172.16.0.0/12
192.168.0.0/16
> ./ipnet-exclude.py rfc1918.txt
0.0.0.0/5
8.0.0.0/7
11.0.0.0/8
12.0.0.0/6
16.0.0.0/4
32.0.0.0/3
64.0.0.0/2
128.0.0.0/1
128.0.0.0/2
128.0.0.0/3
160.0.0.0/5
168.0.0.0/6
172.0.0.0/12
172.32.0.0/11
172.64.0.0/10
172.128.0.0/9
173.0.0.0/8
174.0.0.0/7
176.0.0.0/4
192.0.0.0/2
192.0.0.0/9
192.128.0.0/11
192.160.0.0/13
192.169.0.0/16
192.170.0.0/15
192.172.0.0/14
192.176.0.0/12
192.192.0.0/10
193.0.0.0/8
194.0.0.0/7
196.0.0.0/6
200.0.0.0/5
208.0.0.0/4
224.0.0.0/3
> ./ipnet-exclude.py 127.0.0.1
0.0.0.0/2
64.0.0.0/3
96.0.0.0/4
112.0.0.0/5
120.0.0.0/6
124.0.0.0/7
126.0.0.0/8
127.0.0.0/32
127.0.0.2/31
127.0.0.4/30
127.0.0.8/29
127.0.0.16/28
127.0.0.32/27
127.0.0.64/26
127.0.0.128/25
127.0.1.0/24
127.0.2.0/23
127.0.4.0/22
127.0.8.0/21
127.0.16.0/20
127.0.32.0/19
127.0.64.0/18
127.0.128.0/17
127.1.0.0/16
127.2.0.0/15
127.4.0.0/14
127.8.0.0/13
127.16.0.0/12
127.32.0.0/11
127.64.0.0/10
127.128.0.0/9
128.0.0.0/1
> ./ipnet-exclude.py 3.0.0.0/8
0.0.0.0/7
2.0.0.0/8
4.0.0.0/6
8.0.0.0/5
16.0.0.0/4
32.0.0.0/3
64.0.0.0/2
128.0.0.0/1