handle SIGTERM, SIGINT, SIGQUIT in TodoAppServier
fix navigation by click;
wait for state before handling user input;
prevent navigation back from root list;
scroll to selected todo-item
mark opened item by sticking out bookmark
no more "undefined" in address bar when opening /somelist;
Merge pull request #7 from abalandin/master

fix navigation by mouse&keys; scroll active item into view; misc fixes