Tasks keep running when you navigate to the home page. We should:
[ ] Warn the user when tasks are running and they try to navigate way (to home page or just close the window)
[ ] End tasks when navigating to home or another puzzle
[ ] Clear finished tasks list when navigating to home or another puzzle (this causes a "task finished" message in the solutions list, when that task was for another puzzle with a matching problem ID)
Tasks keep running when you navigate to the home page. We should: