Add Node 4 support to Travis CI and allows it to fail
Add Node 4 support to Travis CI and allows it to fail

Allows that configuration to fail as I didn't do any test myself.
It will only be safe to remove this once thorough tests are done.

sualko/otr,arlolra/otr,sualko/otr,arlolra/otr,arlolra/otr,sualko/otr,arlolra/otr,sualko/otr