got split and divide by working for ip4, ip6 is broken
fixed for ip6, made divide_by_subnets function stop when pfx = pfx - 1 because we don't want subnets of 1 IP
added divide_by_hosts
updated readme
fixed readme line length
added tests and fixed a few logic errors
updated readme
Merge pull request #7 from wazoo/subnet-math

Additional Subnet Math (wazoo)