Auto merge of #88 - snapview:cgwindowlist, r=jdm

Add CGWindowListCreateImageFromArray()

Just adds a binding to one small function.

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src/display.rs

@@ -91,5 +91,7 @@ extern {
                                    listOptions: CGWindowListOption,
                                    windowId: CGWindowID,
                                    imageOptions: CGWindowImageOption) -> CGImageRef;
-
+    pub fn CGWindowListCreateImageFromArray(screenBounds: CGRect,
+                                            windowArray: CFArrayRef,
+                                            imageOptions: CGWindowImageOption) -> CGImageRef;
 }