travis: add iojs
travis: add iojs

Signed-off-by: Mario Kozjak <947b2c519c3332d13d94177c4da85af132a1ff20@b-interactive.hr>

loffelmacher/node-telnet-client,canha/another-telnet-client,mwilliford/node-telnet-client,VPNht/node-telnet-client,colinmathews/node-telnet-client,EyePulp/node-telnet-client