Added missing texture reload for DirectX
Removed non-WP implementation as it isn't needed
Changed iOS Twitter API to use UIImage

Changed iOS Twitter API to use UIImage instead of string
Fixed iOS Guide crash bug

Fixed the bug where using any GamerServices.Guide functionality on iOS
caused the game to crash
Remove unused usings (Targeting System.Linq)
Replace Linq usages with non-linq implementations.
Remove Linq usage in TouchCollection, don't allow null touches to be provided (matches XNA on WP7), provide our own enumerator implementation (matches XNA)

http://msdn.microsoft.com/en-us/library/microsoft.xna.framework.input.touch.touchcollection.getenumerator.aspx
Merge pull request #2735 from danzel/tidy-linq

Tidy up unnecessary Linq usages
Fixed volume on WP8
Ensure struct enumerator on TouchCollection
Merge pull request #2737 from danzel/touchcollection-enumerator

Ensure struct enumerator on TouchCollection
Merge pull request #2736 from Nezz/wpvolume

Fixed music volume on WP8
Merge pull request #2733 from picobots/develop

Changed iOS Twitter API to use UIImage
Merge pull request #2731 from Nezz/directxtexturereload

Added missing texture reload for DirectX
Missing : in ToString.
Implement CurrentDisplayMode for Windows directx.

Fixes #2619
Implement SupportedDisplayModes for DirectX
Merge pull request #2738 from danzel/current-display-mode

GraphicsAdapter.CurrentDisplayMode for windows directx
Merge pull request #2739 from danzel/supported-display-modes

Implement SupportedDisplayModes for DirectX