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/preferences/static/js/preferences.js

@@ -1,6 +1,6 @@
 define('pgadmin.preferences', [
   'sources/gettext', 'sources/url_for', 'jquery', 'underscore', 'alertify',
-  'pgadmin', 'backform', 'pgadmin.browser', 'pgadmin.backform'
+  'sources/pgadmin', 'backform', 'pgadmin.browser', 'pgadmin.backform'
 ], function(gettext, url_for, $, _, alertify, pgAdmin, Backform, pgBrowser) {
   // This defines the Preference/Options Dialog for pgAdmin IV.
     pgAdmin = pgAdmin || window.pgAdmin || {};