PlaneReflector Support for Side-by-Side Rendering

- The PlaneReflector class now supports side-by-side rendering.  This
does mean that while in this rendering style that all planar reflections
are rendered twice, as reflection is a screen space effect from the eye
point of view.
- Planar reflections now work in the Oculus Rift.
- Modified GuiTSCtrl::onRender() to move up where the rendering style is
defined to just before the reflection manager has its turn.

Engine/source/scene/reflector.h

@@ -202,8 +202,11 @@ public:
    virtual F32 calcScore( const ReflectParams &params );
    virtual void updateReflection( const ReflectParams &params ); 
 
+   /// Set up the GFX matrices
+   void setGFXMatrices( const MatrixF &camTrans );
+
    /// Set up camera matrix for a reflection on the plane
-   MatrixF getCameraReflection( MatrixF &camTrans );
+   MatrixF getCameraReflection( const MatrixF &camTrans );
 
    /// Oblique frustum clipping - use near plane of zbuffer as a clip plane
    MatrixF getFrustumClipProj( MatrixF &modelview );