Update build.bat to use local .nuget\NuGet.exe

build.bat

@@ -4,6 +4,6 @@ call "C:\Program Files (x86)\Microsoft Visual Studio 11.0\vc\vcvarsall.bat" x86
 msbuild /tv:4.0 /t:Build /verbosity:quiet /clp:ErrorsOnly /fl /flp:logfile=BuildErrors.log;ErrorsOnly "/p:Configuration=Release;Platform=Any CPU" SharpYaml.sln
 if NOT ERRORLEVEL 0 pause
 pushd SharpYaml
-..\nuget pack -Symbols -OutputDirectory .. SharpYaml.nuspec
+"..\.nuget\nuget.exe" pack -Symbols -OutputDirectory .. SharpYaml.nuspec
 if NOT ERRORLEVEL 0 pause
 popd