Vertical positioning of remote cursors

[cklokmose]

Remote cursors are not positioned correctly when local transient elements (like HTML inspector or console) are opened.

[cklokmose]

Cursors are now positioned relative to paragraphs and not to the body (falls back to the body if the cursor is not on top of a paragraph). However, there's still an issue if a client hovers their cursor over the console or HTML inspector, then the position will be wrong on other clients.

[cklokmose]

Also it still doesn't work with scrolling in e.g. a full-screen code paragraph.