xslate.go
func DefaultVM(tx *Xslate, args Args) error {
	dvm := vm.NewVM()
	dvm.Loader = tx.Loader
	tx.VM = dvm
	return nil
}
func DefaultVM(tx *Xslate, args Args) error {
	dvm := vm.NewVM()
	dvm.Loader = tx.Loader
	tx.VM = dvm
	return nil
}
// DefaultVM sets up and assigns the default VM to be used by Xslate