Update path's and configs to work with phoenix 1.3

[mbenatti]

The actual project do not use phx 1.3 context, so the install(mix torch.install exx) are using phx 1.2 path's.

Also the config in brunch-config should have something like that to load the css:

  stylesheets: {
      joinTo: {
        'css/app.css': /^(web|node_modules|css)/
      }
    }

[zberkom]

@mbenatti This has been addressed in the new v2.0.0-rc.1 release candidate