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/app/ServerProtocol.h

@@ -347,6 +347,10 @@ enum {
 	AS_VIEW_SET_FILL_RULE,
 	AS_VIEW_GET_FILL_RULE,
 
+	// New clipping: cumulative, transformed
+	AS_VIEW_CLIP_TO_RECT,
+	AS_VIEW_CLIP_TO_SHAPE,
+
 	AS_LAST_CODE
 };