Warn when a command is not implemented. Fail when no supplied commands are implemented
Warn when a command is not implemented. Fail when no supplied commands are implemented

Rebar currently doesn't give any feedback on an invalid command. This change
makes rebar keep track of how many operations each command triggers, if a
particular command doesn't change the count, there were no modules implementing
it. If at the end of handling all commands, tje count is 0, none of the supplied
commands were valid and ?FAIL is called to trigger a non zero exit status.

platinumthinker/rebar,rebar/rebar3,csyangchen/rebar,cloudant/couchdb-rebar,apache/couchdb-rebar,beni55/rebar,lrascao/rebar,csyangchen/rebar,choptastic/rebar,fabiankrol/rebar3,lrascao/rebar,basho/rebar,matwey/rebar,macintux/rebar,benoitc/rebar3,rebar/rebar,walrusVision/rebar3,GabrielNicolasAvellaneda/rebar,lrascao/rebar,lpgauth/rebar,shkumagai/rebar,erlang/rebar3,linearregression/rebar3,syl20bnr/rebar,bsmr-erlang/rebar,benoitc/rebar3,evnix/rebar,fabiankrol/rebar3,evnix/rebar,oubiwann/rebar,kellymclaughlin/rebar3,paulo-ferraz-oliveira/rebar,beni55/rebar-1,rebar/rebar3,thomasbhatia/rebar,norton/rebar,oubiwann/rebar,thomasbhatia/rebar,CMoH/rebar,cloudant/couchdb-rebar,surik/rebar3,project-fifo/rebar3,syl20bnr/rebar,linearregression/rebar3,lrascao/rebar3,K2InformaticsGmbH/rebar,norton/rebar,scatterbrain/rebar,matwey/rebar,jacktang/rebar,lrascao/rebar,surik/rebar3,basho/rebar,lrascao/rebar,scatterbrain/rebar,norton/rebar3,deadok22/rebar,vladdu/rebar3,shkumagai/rebar,matwey/rebar,fauxsoup/rebar3,sile/rebar3,beni55/rebar-1,choptastic/rebar,jacktang/rebar,apache/couchdb-rebar,csyangchen/rebar,dcarastan/rebar,lpgauth/rebar,processone/rebar3,cloudant/couchdb-rebar,norton/rebar,sile/rebar3,GabrielNicolasAvellaneda/rebar,jbalint/rebar3,norton/rebar,processone/rebar3,SiDen/rebar,dcarastan/rebar,SiDen/rebar,choptastic/rebar,GabrielNicolasAvellaneda/rebar,shkumagai/rebar,CMoH/rebar,paulo-ferraz-oliveira/rebar,K2InformaticsGmbH/rebar,heroku/rebar,bsmr-erlang/rebar,apache/couchdb-rebar,beni55/rebar,deadok22/rebar,matwey/rebar,project-fifo/rebar3,beni55/rebar,blt/rebar3,thomasbhatia/rebar,saleyn/rebar3,bsmr-erlang/rebar,macintux/rebar,platinumthinker/rebar,heroku/rebar,K2InformaticsGmbH/rebar,tsloughter/rebar3,wcy123/rebar,walrusVision/rebar3,zugolosian/rebar3,bsmr-erlang/rebar,oubiwann/rebar,djnym/rebar3,evnix/rebar,fauxsoup/rebar3,matwey/rebar,K2InformaticsGmbH/rebar,rebar/rebar,CMoH/rebar,paulo-ferraz-oliveira/rebar,macintux/rebar,wcy123/rebar,RubberCthulhu/rebar,platinumthinker/rebar,jbalint/rebar3,SiDen/rebar,RubberCthulhu/rebar,blt/rebar3,ferd/rebar3,K2InformaticsGmbH/rebar,fishcakez/rebar3,rebar/rebar,scatterbrain/rebar,syl20bnr/rebar,jacktang/rebar,lpgauth/rebar,dcarastan/rebar,zugolosian/rebar3