commander: Add debug code for displaying the row score

This comes real handy when working on the sort algorithm to see the actual
score it gave to each row.
commander: Sorting: give higher score to complete word matches
commander: Sorting: give higher score for basename matches

Give higher scores for matches inside the last path component, as it is
more likely the user wanted to match it.

For example it helps matching against filenames that share prefix with
another path component, as it would otherwise also match other files
under the same path, making it harder to find the correct file.
Merge pull request #154 from b4n/wip/commander

commander: improve sorting algorithm