Resolve BottomTab options before creating BottomTab icon

lib/android/app/src/main/java/com/reactnativenavigation/viewcontrollers/bottomtabs/BottomTabsController.java

         List<BottomTabOptions> bottomTabOptionsList = new ArrayList<>();
         for (int i = 0; i < tabs.size(); i++) {
             tabs.get(i).setParentController(this);
-            BottomTabOptions tabOptions = tabs.get(i).options.bottomTabOptions;
+            BottomTabOptions tabOptions = tabs.get(i).resolveCurrentOptions().bottomTabOptions;
             if (!tabOptions.icon.hasValue()) {
                 throw new RuntimeException("BottomTab must have an icon");
             }

playground/src/screens/WelcomeScreen.js

                           title: {
                             text: 'React Native Navigation!'
                           }
+                        },
+                        bottomTab: {
+                          text: 'Tab 1',
+                          icon: require('../images/one.png'),
+                          selectedIcon: require('../images/one.png'),
+                          testID: testIDs.FIRST_TAB_BAR_BUTTON
                         }
                       }
                     }
                   }
                 ],
                 options: {
-                  bottomTab: {
-                    text: 'Tab 1',
-                    icon: require('../images/one.png'),
-                    selectedIcon: require('../images/one.png'),
-                    testID: testIDs.FIRST_TAB_BAR_BUTTON
-                  },
                   topBar: {
                     visible: false
                   }