Update styling-the-navigator.md (#1099)

Separated iOS and Android only properties.

docs/styling-the-navigator.md

 
 ```js
 {
-  navigationBarColor: '#000000', // change the background color of the bottom native navigation bar. Android only
+  // Common
   navBarTextColor: '#000000', // change the text color of the title (remembered across pushes)
   navBarTextFontFamily: 'font-name', // Changes the title font
-  navBarTitleTextCentered: true, // Android only. centers the title, default false.
   navBarBackgroundColor: '#f7f7f7', // change the background color of the nav bar (remembered across pushes)
 
   navBarButtonColor: '#007aff', // Change color of nav bar buttons (eg. the back button) (remembered across pushes)
   navBarHideOnScroll: false, // make the nav bar hidden only after the user starts to scroll
   navBarTranslucent: false, // make the nav bar semi-translucent, works best with drawUnderNavBar:true
   navBarTransparent: false, // make the nav bar transparent, works best with drawUnderNavBar:true,
-  topBarElevationShadowEnabled: false, // Android only, default: true. Disables TopBar elevation shadow on Lolipop and above
   navBarNoBorder: false, // hide the navigation bar bottom border (hair line). Default false
   drawUnderNavBar: false, // draw the screen content under the nav bar, works best with navBarTranslucent:true
   drawUnderTabBar: false, // draw the screen content under the tab bar (the tab bar is always translucent)
   statusBarBlur: false, // blur the area under the status bar, works best with navBarHidden:true
   navBarBlur: false, // blur the entire nav bar, works best with drawUnderNavBar:true
   tabBarHidden: false, // make the screen content hide the tab bar (remembered across pushes)
-  statusBarColor: '#000000', // change the color of the status bar. Android only
   statusBarHideWithNavBar: false // hide the status bar if the nav bar is also hidden, useful for navBarHidden:true
   statusBarHidden: false, // make the status bar hidden regardless of nav bar state
   statusBarTextColorScheme: 'dark', // text color of status bar, 'dark' / 'light' (remembered across pushes)
   statusBarTextColorSchemeSingleScreen: 'light' // same as statusBarTextColorScheme but does NOT remember across pushes
-  collapsingToolBarImage: "http://lorempixel.com/400/200/", // Collapsing Toolbar image. Android only
-  collapsingToolBarImage: require('../../img/topbar.jpg'), // Collapsing Toolbar image. Either use a url or require a local image. Android only
-  collapsingToolBarCollapsedColor: '#0f2362', // Collapsing Toolbar scrim color. Android only
   navBarSubtitleColor: 'red', // subtitle color
   screenBackgroundColor: 'white', // Default screen color, visible before the actual react view is rendered
   orientation: 'portrait' // Sets a specific orientation to a modal and all screens pushed to it. Default: 'auto'. Supported values: 'auto', 'landscape', 'portrait'
-  disabledBackGesture: false, // disable the back gesture (swipe gesture) in order to pop the top screen. Default is false. iOS Only
-  screenBackgroundImageName: '<name of image in Images.xcassets>', // Optional. default screen background image. iOS only
+  
+  // iOS only
+  disabledBackGesture: false, // default: false. Disable the back gesture (swipe gesture) in order to pop the top screen. 
+  screenBackgroundImageName: '<name of image in Images.xcassets>', // Optional. default screen background image.
+  
+  // Android only
+  navigationBarColor: '#000000', // change the background color of the bottom native navigation bar.
+  navBarTitleTextCentered: true, // default: false. centers the title.
+  topBarElevationShadowEnabled: false, // default: true. Disables TopBar elevation shadow on Lolipop and above
+  statusBarColor: '#000000', // change the color of the status bar.
+  collapsingToolBarImage: "http://lorempixel.com/400/200/", // Collapsing Toolbar image.
+  collapsingToolBarImage: require('../../img/topbar.jpg'), // Collapsing Toolbar image. Either use a url or require a local image.
+  collapsingToolBarCollapsedColor: '#0f2362', // Collapsing Toolbar scrim color.
 }
 ```