WPF and regular Win32 windows are now supported

Added support for dragging target on WPF windows and building simple
xpath statements.  Fixed some null results in native library and
increased performance of enumerating wpf windows.  Still need to tweak
filters for picking up Silverlight handles too.

src/org/synthuse/Api.java

@@ -129,6 +129,7 @@ public class Api {
 		boolean EnumChildWindows(HWND hWnd, WNDENUMPROC lpEnumFunc, Pointer data);
 		HWND GetParent(HWND hWnd);
 		boolean IsWindowVisible(HWND hWnd);
+		boolean IsWindow(HWND hWnd);
 		
 		int GetWindowRect(HWND hWnd, RECT r);
 		int MapWindowPoints(HWND hWndFrom, HWND hWndTo, RECT r, int cPoints);