Add  import for moduleFor.

We need to import moduleFor here too.

Btw, I've been trying to run `Broccoli` but I keep getting  the following issue.

        $ bro build dist
        TypeError: Property 'undefined' of object [object Object] is not a function
            at Filter.processString (/Users/adolfo/code/ember-qunit/node_modules/broccoli-dist-es6-module/node_modules/broccoli-es6-module-filter/index.js:63:52)
            at Filter.processFile (/Users/adolfo/code/ember-qunit/node_modules/broccoli-dist-es6-module/node_modules/broccoli-es6-module-filter/node_modules/broccoli-filter/index.js:119:33)