Some cosmetic changes.

- Loading 'pgadmin' as 'sources/pgadmin', as found under the 'sources'
  reference directory to be consistent with other files.
- Removed the 'pgadmin' reference from the base.html template.
- Renamed 'pgadmin.slickgrid.editors.js', and
  'pgadmin.slickgrid.formatters.js' as 'editors.js', and 'formatters.js'
  respectively, as they're already in the 'pgadmin/static/js/slickgrid'
  directory.
- Removed the duplicate entry of 'translations' from the webpack.shim.js

web/pgadmin/static/bundle/app.js

@@ -1,5 +1,5 @@
 define('app', [
-  'babel-polyfill', 'pgadmin', 'bundled_browser', 'pgadmin.datagrid'
+  'babel-polyfill', 'sources/pgadmin', 'bundled_browser', 'pgadmin.datagrid'
   ], function() {
     var initializeModules = function(Object) {
       for (var key in Object) {