- Made receive_file_entry() return the file_struct pointer instead

- Made receive_file_entry() return the file_struct pointer instead
  of storing it into the files[] array.
- Made flist_find() return "no match" if the found item differs in
  its directory-ness from the search item.
- Changed f_name_cmp() to sort sub-directories after non-directories
  for each directory's contents.  This makes things like the upcoming
  --fuzzy patch easier to get right.
- One complicating factor is that clean_flist() needed some extra
  code to ensure that a directory doesn't duplicate a non-directory
  of the same name.
- Make sure that the "strip_root" code in clean_flist() (for relative
  paths) strips off all leading slashes.