Share view

• be able to share what part of the draft people are looking at
• be able to follow someone's view
• if people are following your view, be able to pause the following of view
• interaction pauses following of someone's view
• following someone's view uses the same zoom level and centers their view on your screen - if you have a smaller screen, you will see a smaller amount
• show frame of what chosen person / smallest screen can see so can position shared screen correctly (share will still be full size, but will show correctly on small screen
• map (#11) showing where people are looking over the entire drawing(s)