Update NugetWrapper.cmd to download nuget.exe from nuget.org and cache locally instead of using internal share (#94)

tools/NugetWrapper.cmd

@@ -3,6 +3,11 @@ setlocal
 
 set VisualStudioVersion=15.0
 
-\\edge-svcs\nuget\v4.6.2\NuGet.exe %*
+if not exist %TEMP%\nuget.4.9.2.exe (
+    echo Nuget.exe not found in the temp dir, downloading.
+    powershell -Command "& { Invoke-WebRequest https://dist.nuget.org/win-x86-commandline/v4.9.2/nuget.exe -outfile $env:TEMP\nuget.4.9.2.exe }"
+)
 
-exit /B %ERRORLEVEL%
+%TEMP%\nuget.4.9.2.exe %*
+
+exit /B %ERRORLEVEL%