bug: marking as done uses unsorted index

[jpouellet]

Steps to reproduce:

test-todo.txt:

(A) first
(B) second

todotxt-machine -f ./test-todo.txt

• sort in decending order (s s)
• (B) second (now at the top of the list) should be selected
• mark as done (x)
• quit (q)

Notice that that (A) first gets marked as done instead. (and this is not the line selected while pressing x)

resulting test-todo.txt:

(B) second
x 2014-07-25 (A) first

[AnthonyDiGirolamo]

That was worse than I thought, editing an item when reverse sorted would updated the wrong todo also. Fixed now :-)