Build config option for other files

[jasonmcaffee]

Provide a build option to include any other js files.
Should be at the file level.

modulus.build({
    dist:{
         files:{
             './dist/someFile.js': {
                 include:[
                     {
                        path: './src/vendor/metrics.js',
                        locationInDistFile: 'bottom' //place at the bottom of built file
                      }
                 ]
             }
         }
    }
});