Add 2 features, change 1 IP website, code cleanup

- add --force feature
- remove unused LWP::UserAgent
- requires IO::Socket::INET
- add icanhazip.com (ip4/ip6/georedundant)
- remove showmyip.com (unreachable)
- fix use of unitialized conf variable (i.e. "Notify = ")
- replace 4-space tabs with tabs (was all mixed up, beautified)