Added test cases for reopen and closing todos and counting.
Added test cases for reopen and closing todos and counting.

rtzll/flask-todolist,rtzll/flask-todolist,guillaumededrie/flask-todolist,poulp/flask-todolist,rtzll/flask-todolist,guillaumededrie/flask-todolist,poulp/flask-todolist,0xfoo/flask-todolist,polyfunc/flask-todolist,polyfunc/flask-todolist,polyfunc/flask-todolist,rtzll/flask-todolist,0xfoo/flask-todolist,poulp/flask-todolist,guillaumededrie/flask-todolist,0xfoo/flask-todolist