Minified js (#485)

no issue

- Added a `js` task to run on the gulp build process and minifies our js files
- Changed the required scripts in `default.hbs` to use the minified js files in `/built/`
- Moved existing `js` tasks from `zip` task

default.hbs

@@ -73,7 +73,7 @@
         integrity="sha256-hwg4gsxgFZhOsEEamdOYGBf13FyQuiTwlAQgxVSNgt4="
         crossorigin="anonymous">
     </script>
-    <script type="text/javascript" src="{{asset "js/jquery.fitvids.js"}}"></script>
+    <script type="text/javascript" src="{{asset "built/jquery.fitvids.js"}}"></script>
 
     {{#if pagination.pages}}
     <script>
@@ -82,7 +82,7 @@
         // we reached the last page already.
         var maxPages = parseInt('{{pagination.pages}}');
     </script>
-    <script src="{{asset "js/infinitescroll.js"}}"></script>
+    <script src="{{asset "built//infinitescroll.js"}}"></script>
     {{/if}}
 
     {{!-- The #block helper will pull in data from the #contentFor other template files. In this case, there's some JavaScript which we only want to use in post.hbs, but it needs to be included down here, after jQuery has already loaded. --}}