Make collection page icon actionable: jump to page

[artasparks]

For long SGF Collections, it would be nice to be able to jump to problem / page. The most logical way to support this would be to turn the page-icon into button that opened up a game-info like window that allowed you to click on the relevant part.

This will probably mean changing the game info window overlay slightly. It's probably a bad user experience to close the page/section window on any old click -- it should only close when the user has clicked on a new page or a 'close' icon or something like that.

[artasparks]

Definitely a top priority now. Will probably be in 1.0.4