Implement add notes to eBook PDF pages in Readings fragments

[lschmid83]

I would like to add a feature to the Readings fragments where users can add notes to pages of the readings basic text PDF eBooks. I have thought about this and it should be relatively easy to add a button similar to the already existing Go To Page in the top right corner of the eBook reader. This would open a simple fragment with a text entry box to add notes which could then be saved to the MySQL database. There is an issue where if this feature is every implemented there must be a method of backing up the data so that users don't lose their important notes.