[Toolkit.Input] Breaking changes of KeyboardState.  Now contains one states for Down keys and two events Pressed/Released since last frame.
[Toolkit.Input] Change behavior of buttons handling for MouseManager using new ButtonState. Refactor code using ButtonState.
[Toolkit.Graphics] Remove assert on DDSHelper when creating an image
[Toolkit.Game] Fix issue #237. Remove redundant code
[DXGI] Fix issue #244. Remove partial typeless format from FormatHelper.IsTypeLess for formats:  R32_Float_X8X24_Typeless/X32_Typeless_G8X24_UInt and R24_UNorm_X8_Typeless/X24_Typeless_G8_UInt
[Toolkit.Input] Fix issue on WinRT for released moust buttons
[Toolkit.Samples] Fix compilation issue on WinRT for MouseInput
[Toolkit.Samples] Fix compilation issues on desktop
[Toolkit.Graphics] Fix issue #236 with SpriteFont layout
[Toolkit.Graphics] Fix calculation for mipmap counts
[SharpGen] Fix issue #234. Error message was not clear
Merge remote-tracking branch 'upstream/master'