Improve Viatom file selection on Windows.

Also remove a warning about unexpected data.

oscar/SleepLib/loader_plugins/viatom_loader.cpp

@@ -303,11 +303,8 @@ bool ViatomFile::ParseHeader()
     //int spo2_avg = header[17];
     //int spo2_min = header[18];
     //int spo2_3pct = header[19];  // number of events
-    int spo2_4pct = header[20];  // number of events
-    if (header[21] > spo2_4pct) {
-        //CHECK_VALUE(header[21], 0);  // sometimes nonzero; maybe spo2_5pct or something like that?
-        UNEXPECTED_VALUE(header[21], "< drops over 4%");
-    }
+    //int spo2_4pct = header[20];  // number of events
+    //CHECK_VALUE(header[21], 0);  // ??? sometimes nonzero; maybe pulse spike, not a threshold of SpO2 or pulse, not always smaller than spo2_4pct
     //int time_under_90pct = header[22] | (header[23] << 8);  // in seconds
     //int events_under_90pct = header[24];  // number of distinct events
     //float o2_score = header[25] * 0.1;

oscar/mainwindow.cpp

@@ -2504,10 +2504,17 @@ void MainWindow::on_actionImport_Viatom_Data_triggered()
 #if defined(Q_OS_WIN)
     // Windows can't handle this name filter.
     w.setOption(QFileDialog::DontUseNativeDialog, true);
+    // And since the non-native dialog can't select both directories and files,
+    // it needs the following to enable selecting multiple files.
+    w.setFileMode(QFileDialog::ExistingFiles);
 #endif
 
     if (w.exec() == QFileDialog::Accepted) {
         QString filename = w.selectedFiles()[0];
+        if (w.selectedFiles().size() > 1) {
+            // The user selected multiple files in a directory, so use the parent directory as the filename.
+            filename = QFileInfo(filename).absoluteDir().canonicalPath();
+        }
 
         int c = viatom.Open(filename);
         if (c > 0) {