CB-8467

Added support for hiding the web view container.  This maintains the browser
session without closing it.  The browser window can be repeatedly hidden and
shown.

** This has only been tested on android and ios **

amazon/android:
An additional `hide` action was added to `InAppBrowser#execute`.  It is
identical to `show`, except that it calls `dialog.hide()` instead.

blackberry10:
no changes

firefoxos:
Added a `hide` method that is identical to `show`, indicating it is not
supported.

ios:
Added a `hide` method that is identical to `show`, except that it uses
`dismissViewControllerAnimated`.  It checks the value of
`_previousStatusBarStyle`.  If it is `-1`, the method returns with no
action performed.  If it is not, it is set to `-1.`

ubuntu:
Added a `hide` method that sets `CordovaWrapper.global.inappbrowser.visible` to
`false`.

windows:
Added a `hide` method that sets `browserWrap.style.display` to `none`.

wp:
Added a `hide` method that is identical to `show`, except that it sets
`browser.Visibility` to `Visibility.Collapsed` and sets `AppBar.IsVisible` to
`false`.

README.md

@@ -216,6 +216,7 @@ The object returned from a call to `cordova.InAppBrowser.open` when the target i
 - removeEventListener
 - close
 - show
+- hide
 - executeScript
 - insertCSS
 
@@ -414,6 +415,27 @@ The function is passed an `InAppBrowserEvent` object.
     // some time later...
     ref.show();
 
+## InAppBrowser.hide
+
+> Hides the InAppBrowser window. Calling this has no effect if the InAppBrowser was already hidden.
+
+    ref.hide();
+
+- __ref__: reference to the InAppBrowser window (`InAppBrowser`)
+
+### Supported Platforms
+
+- Amazon Fire OS
+- Android
+- iOS
+- Windows 8 and 8.1
+
+### Quick Example
+
+    var ref = cordova.InAppBrowser.open('http://apache.org', '_blank');
+    // some time later...
+    ref.hide();
+
 ## InAppBrowser.executeScript
 
 > Injects JavaScript code into the `InAppBrowser` window
@@ -683,4 +705,4 @@ iab.open('http://url-that-fails-whitelist.com', '_blank');        // loads in th
 iab.open('http://url-that-fails-whitelist.com', 'random_string'); // loads in the InAppBrowser
 iab.open('http://url-that-fails-whitelist.com', 'random_string', 'location=no'); // loads in the InAppBrowser, no location bar
 
-```
+```