Moved the return link above the inline discussion and updated the header styling so the hide annotations button is right-aligned with the help icon.

Updated markup, styling, and tooltip behavior for displaying instructor comments. Added drag/drop to the comments so the user can organize them as they wish after clicking on the span. When the user hides the annotations, their positions on the screen are remembered so they can be restored later. Also modified the markup so that block content can be displayed.

Modified annotatable to retrieve and display instructor comments from span elements. Instructor commentaries are displayed in tooltips with a reply link when the highlighted area is clicked. The commentaries are connected to inline discussion forums by anchors (for now).