To track if cell was changed you can use the afterChange hook. Here’s the updated demo: http://jsfiddle.net/Lc0sk46g/
I’m logging the row data only if the change wasn’t made via loadData. You can add more exceptions like to log the data only when the cell was edited
if(changes === 'edit')
or when new value of the cell is different from the one that was before
if(src[0][2] !== src[0][3])
ps. if you would like yo block a change then it’s recommended to choose ‘beforeChange’ hook.