Improve performance and cosmetics

- reduced the load time of the preview modal assets
- changed cursor to ‘pointer’ for modal buttons

src/components/browser-modal/browser-modal.css

@@ -56,6 +56,7 @@
     color: white;
     font-weight: bold;
     font-size: 0.875rem;
+    cursor: pointer;
 }
 
 .faq-link-text {

src/components/preview-modal/preview-modal.css

@@ -55,6 +55,7 @@
     background: white;
     font-weight: bold;
     font-size: .875rem;
+    cursor: pointer;
 }
 
 .button-row button.ok-button {

src/components/preview-modal/preview-modal.jsx

@@ -5,7 +5,7 @@ import Box from '../box/box.jsx';
 import {defineMessages, injectIntl, intlShape, FormattedMessage} from 'react-intl';
 
 import styles from './preview-modal.css';
-import catIcon from './happy-cat.svg';
+import catIcon from './happy-cat.png';
 
 const messages = defineMessages({
     label: {