Display annotations on sidebar like Hypothes.is

Now the annotations can only show up in a pop--up after clicking the annotated text or image parts. It would be much more friendly like https://hypothes.is as the screenshot below:

The most important features are:

1. Display all the annotations on the sidebar area;
2. We can expand or collapse the sidebar area;
3. The correspondent annotations will display highlightly when clicking the annotated text or image parts;
4. Number of annotations also displays per paragraph.