app_server/Interface Kit: add new clipping API

* Add new clipping API for rectangles (ClipToRect, ClipToInverseRect)
  and shapes (ClipToShape, ClipToInverseShape)

* Works with affine transforms and automatically switches from fast
  region-based clipping to alpha-mask based clipping as necessary.

* Always self-intersecting, i.e. no state push required to further
  narrow down the clipping region. All of the 4 new methods can be
  mixed in any order.

headers/private/interface/PictureDataWriter.h

@@ -96,6 +96,11 @@ public:
 									const int32& token);
 
 			status_t			WriteBlendLayer(Layer* layer);
+			status_t			WriteClipToRect(const BRect& rect,
+									bool inverse);
+			status_t			WriteClipToShape(int32 opCount,
+									const void* opList, int32 ptCount,
+									const void* ptList, bool inverse);
 
 protected:
 	// throw a status_t on error