add prop types about tabbar's styles (#1041)

Author: ma96o

index.js

@@ -38,6 +38,11 @@ const ScrollableTabView = createReactClass({
     onChangeTab: PropTypes.func,
     onScroll: PropTypes.func,
     renderTabBar: PropTypes.any,
+    tabBarUnderlineStyle: ViewPropTypes.style,
+    tabBarBackgroundColor: PropTypes.string,
+    tabBarActiveTextColor: PropTypes.string,
+    tabBarInactiveTextColor: PropTypes.string,
+    tabBarTextStyle: PropTypes.object,
     style: ViewPropTypes.style,
     contentProps: PropTypes.object,
     scrollWithoutAnimation: PropTypes.bool,