Fix failures in iOS 9

There appear to be some changes in the recent Rubymotion updates (I
haven't been able to find where) that means some specs were failing when
run with iOS 9 as the target.

This change introduces a fix specifically to the `Constants.get` method
as used by `UIActivityViewController`.

The error was, passing activities to exclude from the activity view
caused an error where an Array was expected but the splat wasn't
creating one.

The other issue this fixes is to delegate the `tag` property on a
`UINavigationViewItem` to it's child `UIBarButtonItem` in the test
implementation (a `UINavigationViewItem` doesn't have a `tag` property).

Gemfile.lock

@@ -1,7 +1,7 @@
 PATH
   remote: .
   specs:
-    bubble-wrap (1.9.4)
+    bubble-wrap (1.9.5)
 
 GEM
   remote: https://rubygems.org/
@@ -27,4 +27,4 @@ DEPENDENCIES
   webstub (~> 1.1)
 
 BUNDLED WITH
-   1.10.4
+   1.10.6

motion/util/constants.rb

@@ -24,6 +24,7 @@ def register(*ui_constants)
     # get("UIImagePickerControllerSourceType", ["photo_library", "camera", "saved_photos_album"]) => 3
     # get("UIActivityType", [:air_drop, :print]) => ["com.apple.UIKit.activity.AirDrop", "com.apple.UIKit.activity.Print"]
     def get(base, *values)
+      values = Array(values)
       value = values.size == 1 ? values.first : values.flatten
       case value
       when Numeric

spec/motion/ui/ui_bar_button_item_spec.rb

@@ -23,6 +23,14 @@ def dealloc
       App.notification_center.post('NavigationItemContainingBarButtonItem dealloc', nil, {'tag'=>tag})
       super
     end
+
+    def tag
+      leftBarButtonItem.tag
+    end
+
+    def tag=(value)
+      leftBarButtonItem.tag = value
+    end
   end
 
   describe ".styled" do