app_server & interface kit: support fill rules.

* BView gets SetFillRule/FillRule methods. The fill rule is part of the
view state.
* The B_NONZERO rule is the default. This is what we implemented before.
* The B_EVEN_ODD rule is the other common possibility for this, and
we need to support it to help WebKit to render properly.

headers/os/interface/View.h

@@ -282,6 +282,9 @@ public:
 			cap_mode			LineCapMode() const;
 			float				LineMiterLimit() const;
 
+			void				SetFillRule(int32 rule);
+			int32				FillRule() const;
+
 			void				SetOrigin(BPoint pt);
 			void				SetOrigin(float x, float y);
 			BPoint				Origin() const;