Hello.

I made a function sorting by version in `ls-lisp-handle-switches', by
setting `dired-listing-switches' to "-alv".

At first, I made `string-version-lessp', by referring to
`glibc-2.11.1/string/strverscmp.c'.
But I was not satisfied with the spec.
So I made another function `string-logical-lessp'.

If no problems, please apply to `ls-lisp.el'.

Example:

  (sort '(
          "abc-1.0051.tgz"
          "abc-1.00501.tgz"
          "abc-1.007.tgz"
          "abc-1.012b.tgz"
          "abc-1.01a.tgz"
          )
        'string-logical-lessp)
  =>
  ("abc-1.01a.tgz"
   "abc-1.007.tgz"
   "abc-1.012b.tgz"
   "abc-1.0051.tgz"
   "abc-1.00501.tgz")

  (dired "d:/test/")
  =>
    d:/test:
    total used in directory 0 available 20000000
    drwxrwxrwx  1 Administrators none    0 Mar  7 12:03 .
    dr-xr-xr-x  1 Administrators none    0 Mar  7 12:23 ..
    -rw-rw-rw-  1 Administrators none    0 May  7 12:57 7
    -rw-rw-rw-  1 Administrators none    0 May  7 12:57 8
    -rw-rw-rw-  1 Administrators none    0 May  7 12:57 9
    -rw-rw-rw-  1 Administrators none    0 May  7 12:57 10
    -rw-rw-rw-  1 Administrators none    0 May  7 12:57 11
    -rw-rw-rw-  1 Administrators none    0 May  7 12:57 12
    -rw-rw-rw-  1 Administrators none    0 Mar  7 12:57 abc-1.01a.tgz
    -rw-rw-rw-  1 Administrators none    0 Mar  7 12:57 abc-1.007.tgz
    -rw-rw-rw-  1 Administrators none    0 Mar  7 12:57 abc-1.012b.tgz
    -rw-rw-rw-  1 Administrators none    0 Mar  7 12:57 abc-1.0051.tgz
    -rw-rw-rw-  1 Administrators none    0 Mar  7 12:57 abc-1.00501.tgz