BuildTundra.cmd fix when cmake generator string is passed.
BuildTundra.cmd fix when cmake generator string is passed.

realXtend/tundra-urho3d,realXtend/tundra-urho3d,realXtend/tundra-urho3d,realXtend/tundra-urho3d,realXtend/tundra-urho3d