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.

native/WpfBridge/WpfBridge.vcxproj

@@ -148,6 +148,7 @@ copy /Y "$(TargetPath)" "$(ProjectDir)bin\wpfbridge$(PlatformArchitecture)$(Targ
     <Reference Include="UIAutomationClient" />
     <Reference Include="UIAutomationProvider" />
     <Reference Include="UIAutomationTypes" />
+    <Reference Include="WindowsBase" />
   </ItemGroup>
   <ItemGroup>
     <ClInclude Include="Global.h" />