Fix config loading in shell
Fix config loading in shell

Config files from the command line would expect the wrong format:

    {app1, [...]}.
    {app2, [...]}.

Instead of the correct sys.config format:

    [{app1, [...]},
     {app2, [...]}]

Not supported yet: the recursive file references documented in
http://www.erlang.org/doc/man/config.html

rebar/rebar3,fauxsoup/rebar3,linearregression/rebar3,djnym/rebar3,jbalint/rebar3,norton/rebar3,surik/rebar3,tsloughter/rebar3,fauxsoup/rebar3,vladdu/rebar3,lrascao/rebar3,erlang/rebar3,saleyn/rebar3,sile/rebar3,sile/rebar3,zugolosian/rebar3,ferd/rebar3,blt/rebar3,benoitc/rebar3,walrusVision/rebar3,blt/rebar3,surik/rebar3,benoitc/rebar3,processone/rebar3,fabiankrol/rebar3,zugolosian/rebar3,linearregression/rebar3,project-fifo/rebar3,rebar/rebar3,walrusVision/rebar3,project-fifo/rebar3,processone/rebar3,fabiankrol/rebar3,jbalint/rebar3