[minor] some tweaks (convenience)

[update] raising PickingFailedException when CF cannot be calculated due to missing signal (too short waveform)

PyLoT.py

@@ -3687,10 +3687,13 @@ class MainWindow(QMainWindow):
         if not self.okToContinue():
             return
         if not fnm:
-            dlg = QFileDialog(parent=self)
+            settings = QSettings()
+            dir = settings.value('current_project_path')
+            dlg = QFileDialog(parent=self, directory=dir)
             fnm = dlg.getOpenFileName(self, 'Open project file...', filter='Pylot project (*.plp)')[0]
             if not fnm:
                 return
+            settings.setValue('current_project_path', os.path.split(fnm)[0])
         if not os.path.exists(fnm):
             QMessageBox.warning(self, 'Could not open file',
                                 'Could not open project file {}. File does not exist.'.format(fnm))

pylot/core/pick/picker.py

@@ -199,7 +199,7 @@ class AICPicker(AutoPicker):
         # minimum in AIC function 
         icfmax = np.argmax(cf)
 
-        # MP MP testing threshold
+        # TODO: If this shall be kept, maybe add thresh_factor to pylot parameters
         thresh_hit = False
         thresh_factor = 0.7
         thresh = thresh_factor * cf[icfmax]
@@ -211,7 +211,6 @@ class AICPicker(AutoPicker):
                 if sample <= cf[index - 1]:
                     icfmax = index - 1
                     break
-        # MP MP ---
 
         # find minimum in AIC-CF front of maximum of HOS/AR-CF
         lpickwindow = int(round(self.PickWindow / self.dt))