Fix single sided stencil

When not using TwoSidedStencilMode the same sttings must apply to both
FrontFace and BackFace.

This fixed a transition that creates a stencil mask and happened to be
CounterClockWise. Resualts are now same as XNA.
Merge pull request #1193 from nkast/nkastBranch2

Fix single sided stencil