Made filling aware of fill of children
Made filling aware of fill of children

This fix is somewhat controversial, if you apply a fill to a container, and the children of the container have fills, then the "deepest" fill is kept. However, this breaks the default black that is now applied to shapes because shapes would then not be fillable anymore. So the question is if we want that.

CanvasHS/Canvas.hs,CanvasHS/Canvas.hs