Better algorithm for sorting folders, sorting each path part one by one.
Better algorithm for sorting folders, sorting each path part one by one.

* src/widgets/modest-folder-view.c (cmp_rows): new method compare_folders
  that compare the folder paths taking into account the path separators. Now
  we compare each part of the path one by one, to have the proper comparison
  (fixes NB#119818).

community-ssu/modest,community-ssu/modest,community-ssu/modest,community-ssu/modest