Duolingo Notes

Duolingo Notes can help you save notes during learning.

Features:
1. bookmark the question and answer during learning.
2. Review your bookmarked notes.
3. Copy the note.
4. Speak the note.
5. Add personal comments.
6. Search the note.
7. Delete the note.
8. Delete all notes.
9. Export notes to CSV.
10. Add shortcut key (Alt+A) to add note.

Source code is available at https://github.com/JakeLin/DuolingoNotes
User Guide is available at https://www.duolingo.com/comment/2976444

Release Notes
* V1.9
Add delete all notes button. Add export notes to CSV feature. Thanks to [northernguy](https://www.duolingo.com/northernguy) for suggesting these features.

* V1.8
Support image select question.

* V1.7
Improve User Experience, show bigger image when mouse hover over, add tooltip for buttons, resize the popup and display better for Windows users.

* V1.6
Use chrome.storage.local to replace chrome.storage.sync due to the storage limit of chrome.storage.sync (https://developer.chrome.com/extensions/storage#type-StorageArea). Thanks to [northernguy](https://www.duolingo.com/northernguy) for reporting that.

* V1.5
Added Support to Practice Lesson(practicing/strengthening a lesson). The user can add notes during Practice Lesson. Thanks to [jan williams](https://www.duolingo.com/willijanb) for reporting that.

* V1.4
Added tooltip for personal comments. Thanks to [Dessamator](https://www.duolingo.com/Dessamator) for suggesting this feature.

* V1.3
Added personal comments box.

* V1.2
Added speech button.