Add the latest OTP 18 version to the Travis build
Add the latest OTP 18 version to the Travis build

apache/couchdb-rebar,bsmr-erlang/rebar,jacktang/rebar,choptastic/rebar,matwey/rebar,lrascao/rebar,paulo-ferraz-oliveira/rebar,norton/rebar,matwey/rebar,jacktang/rebar,oubiwann/rebar,norton/rebar,rebar/rebar,bsmr-erlang/rebar,matwey/rebar,oubiwann/rebar,apache/couchdb-rebar,apache/couchdb-rebar,K2InformaticsGmbH/rebar,choptastic/rebar,K2InformaticsGmbH/rebar,K2InformaticsGmbH/rebar,oubiwann/rebar,bsmr-erlang/rebar,lrascao/rebar,lrascao/rebar,K2InformaticsGmbH/rebar,matwey/rebar,jacktang/rebar,lrascao/rebar,rebar/rebar,matwey/rebar,rebar/rebar,paulo-ferraz-oliveira/rebar,K2InformaticsGmbH/rebar,choptastic/rebar,bsmr-erlang/rebar,paulo-ferraz-oliveira/rebar,norton/rebar,lrascao/rebar,norton/rebar