MBlockScrollStencil X1.w,Y1.w,Width.w,Height.w,X2.w,Y2.w[,SourceBitmapNum.w] ; BlockCopy stencil to stencil

Does the same as MBlockScroll except with regards to the stencils of chunky
Bitmaps. The Bitmap's stencil will be copied into another Bitmap's stencil. Width,
X1 and X2 should be multiples of 16.