Merge
[text_view_comments] To allow scrolling in Safari mobile, we set the content of text_view_comments frame in a jQuery UI layout.
[c_sync.js] So the automated scrolling operations in c_sync.js must be adjustable to the right part to scroll.
[c_sync.js] Also, if a comment have to be shown outside of the current viewport, we scroll the correct part to that viewport
and then set the comment top Y offset to juste what it needs to avoid the "Add comment" button after scrolling
operation.
[c_sync.js] If not in Safari mobile, we add an offset here to avoid comment to display under the "Add comment" button.