Fix Gruntfile and localization scripts to pass build, fixes https://github.com/mozilla/thimble.mozilla.org/issues/1670

Gruntfile.js

@@ -93,9 +93,11 @@ module.exports = function (grunt) {
 
                         /* extensions and CodeMirror modes */
                         '!extensions/default/*/unittests.js',
-                        'extensions/default/*/**/*.*',
+                        'extensions/default/*/**/*.js',
                         '!extensions/extra/*/unittests.js',
-                        'extensions/extra/*/**/*.*',
+                        'extensions/extra/*/**/*.js',
+                        '!extensions/**/node_modules/**/*.js',
+                        '!extensions/**/test/**/*.js',
                         '!**/unittest-files/**',
                         'thirdparty/CodeMirror/addon/{,*/}*.js',
                         'thirdparty/CodeMirror/keymap/{,*/}*.js',

scripts/properties2js.js

@@ -94,7 +94,7 @@ function localizeBrackets(locale) {
             return Promise.resolve();
         }
 
-        if(isNewLocale) {
+        if(isNewLocale && (destLocales.indexOf(localeDir) === -1)) {
             destLocales.push(localeDir);
         }