change nyancat telnet server

miku.acm.uiuc.edu was decommissioned a while ago; this is a sanctioned mirror
Update nyan.plugin.zsh
Merge pull request #2465 from klange/master

change nyancat telnet server
provides iwhois command to use CNAMES under whois.geek.nz to find most accurate whois server
Merge branch 'plugins/iwhois'