fixes & enhancements

Fixes:
- max threads set based on cpu error, out of range
don't set threads from metadata
don't read metadata props that are set to be excluded
- napari wont quit properly due to 'app = QApplication([])' call in _widgetLF.py which is only required in _widgetLF_test.py to run the plugin from cmd line
- modes button toggle (fixes #47 )
hover image to highlight button feature
mouse cursor to highlight button
- message-box dialogs location
message-box dialogs to use napari look & feel UI and center based on plugin as parent, should ensure dialog is always centered wrt to plugin

Enhancements:
- added preset & comments tooltip
- added neural net training tab
start NN training jupyter notebook from plugin in separate thread
- added metadata.txt to example datasets
- added button to Reset Project Directory folder to default under Misc

src/napari_lf/_widgetLF.py

@@ -9,7 +9,7 @@
 
 # Fix for the QPixMap error
 # https://github.com/PolarizedLightFieldMicroscopy/napari-LF/issues/29
-app = QApplication([])
+# app = QApplication([])
 
 try:
 	from napari_lf import _widgetLF_gui as LFgui
@@ -267,14 +267,17 @@ def input_model_change_call():
 		if "mode_choice" in self.gui.settings["main"] and self.gui.settings["main"]["mode_choice"] == 'NeuralNet':
 			self.gui.LFAnalyze_btn_cont.hide()
 			self.gui.NeuralNet_btn_cont.show()
+			self.gui.NeuralNet_btn.isButtonActive = True
+			self.gui.LFAnalyze_btn.isButtonActive = False
 			self.gui.widget_main_bottom_comps0.hide()
 			self.gui.widget_main_bottom_comps1.hide()
 			self.gui.widget_main_bottom_comps2.show()
 			self.gui._cont_btn_processing.hide()
 			self.gui._cont_btn_processing2.show()
-			self.gui.NeuralNet_btn.toggle()
+			#self.gui.NeuralNet_btn.toggle()
 		else:
-			self.gui.LFAnalyze_btn.toggle()
+			pass
+			#self.gui.LFAnalyze_btn.toggle()
 
 		#Layout
 		layout = QVBoxLayout()