Made Helvetica sans-serif by default

src/style_manager/model/PropertyFactory.js

@@ -548,7 +548,7 @@ export default () => ({
             'Comic Sans MS, cursive' + ss,
             'Courier New, Courier, monospace',
             'Georgia, serif',
-            'Helvetica, serif',
+            'Helvetica' + ss,
             'Impact, Charcoal' + ss,
             'Lucida Sans Unicode, Lucida Grande' + ss,
             'Tahoma, Geneva' + ss,

test/specs/style_manager/model/Models.js

@@ -664,7 +664,7 @@ describe('PropertyFactory', () => {
         { name: 'Comic Sans MS', value: 'Comic Sans MS, cursive' + ss },
         { name: 'Courier New', value: 'Courier New, Courier' + ms },
         { name: 'Georgia', value: 'Georgia, serif' },
-        { name: 'Helvetica', value: 'Helvetica, serif' },
+        { name: 'Helvetica', value: 'Helvetica' + ss },
         { name: 'Impact', value: 'Impact, Charcoal' + ss },
         {
           name: 'Lucida Sans Unicode',