Add new loadMinimalLoader prop to documentation

Author: Exilz

README.md

@@ -193,6 +193,7 @@ AppRegistry.registerComponent('myproject', () => swiper);
 | style | {...} | `style` | See default style in source. |
 | loadMinimal | false | `bool` | Only load current index slide , `loadMinimalSize` slides before and after. |
 | loadMinimalSize | 1 | `number` | see `loadMinimal`   |
+| loadMinimalLoader | `<ActivityIndicator />` | `element` | Custom loader to display when slides aren't loaded
 
 #### Pagination