InputStream: add virtual destructor

Replaces the method Close().

test/dump_playlist.cxx

@@ -105,7 +105,7 @@ int main(int argc, char **argv)
 
 		playlist = playlist_list_open_stream(*is, uri);
 		if (playlist == NULL) {
-			is->Close();
+			delete is;
 			fprintf(stderr, "Failed to open playlist\n");
 			return 2;
 		}
@@ -139,8 +139,7 @@ int main(int argc, char **argv)
 	/* deinitialize everything */
 
 	delete playlist;
-	if (is != NULL)
-		is->Close();
+	delete is;
 
 	decoder_plugin_deinit_all();
 	playlist_list_global_finish();

test/dump_text_file.cxx

@@ -112,7 +112,7 @@ int main(int argc, char **argv)
 	InputStream *is = InputStream::OpenReady(argv[1], mutex, cond, error);
 	if (is != NULL) {
 		ret = dump_input_stream(*is);
-		is->Close();
+		delete is;
 	} else {
 		if (error.IsDefined())
 			LogError(error);

test/read_tags.cxx

@@ -127,7 +127,7 @@ int main(int argc, char **argv)
 		}
 
 		success = plugin->ScanStream(*is, print_handler, nullptr);
-		is->Close();
+		delete is;
 	}
 
 	decoder_plugin_deinit_all();

test/run_decoder.cxx

@@ -230,7 +230,7 @@ int main(int argc, char **argv)
 
 		decoder.plugin->StreamDecode(decoder, *is);
 
-		is->Close();
+		delete is;
 	} else {
 		fprintf(stderr, "Decoder plugin is not usable\n");
 		return EXIT_FAILURE;

test/run_input.cxx

@@ -132,7 +132,7 @@ int main(int argc, char **argv)
 	is = InputStream::OpenReady(argv[1], mutex, cond, error);
 	if (is != NULL) {
 		ret = dump_input_stream(is);
-		is->Close();
+		delete is;
 	} else {
 		if (error.IsDefined())
 			LogError(error);