[SharpDX]comment fixes.

at Matrix.cs
[SharpDX] Add comments

to ViewportF class
[SharpDX]Added comments.

to Viewport.cs(also added Validate methods).
[SharpDX] Comment fixes.

+ small fixes to Viewport
[SharpDX]comment fixes.

at ViewportF.cs
[SharpDX]comment fixes.

at Viewport.cs - final
Issue 379:	BoundingFrustum.GetCorners allocation
 @ fixed
* math tweaks
Merge github.com:OndrejPetrzilka/SharpDX into keenswh
@ math fixes
[Direct3D11] Restore DeviceDebug/InfoQueue for WP8, now accessible on all platforms
Merge branch 'pr/n34_mikrogen'
[SharpDX] Fix Vector4 operator / with Vector4
[Toolkit.Input] Implemented pointer input events for WinRT platform
[Toolkit.Input] Replaced Point struct by SharpDX.DrawingPoint
[Toolkit.Input] added comments for Pointer* classes.
[Toolkit.Input] Handle pointer input for Desktop platform (mouse only)
[Toolkit.Input] made a few methods static
[Toolkit.Input] added pointer input sample for WinRT platform
[Toolkit.Input] added sample pointer input projects for Desktop platform