Sort the news in descending order (newer first).

This fixes bug #150 (consequence of a fix in ocamlrss).
Increase slightly the length for the "header" of a post.
Update OCaml 2013 pages with deadline extension.
Version setup.ml to preserve the OCAML_TOPLEVEL_PATH trick.

Setting the path according to OCAML_TOPLEVEL_PATH will be present in
the next version of oasis but until then, it is necessary to add it by
hand.  setup.ml may be erased by distclean.
Process error messages for both OCaml 3.12 and 4.0
replace JaneSt logos
Merge branch 'master' of github.com:ocaml/ocaml.org
adjust size of JaneSt logo
rename jane-street image file
Merge pull request #154 from ocamllabs/master

Replace Jane St logos
Merge branch 'master' of github.com:ocaml/ocaml.org
Update links for the book "Think OCaml".
Add the book by John Whitington.
Add image for "OCaml from the Very Beginning".
Add book "Real World OCaml".
Books: add Amazon link to Whitington's book
ocaml.css: reduce thickness of error underline
Reverse the RSS order again.

The OCaml RSS module changed the sorting order again.
https://github.com/zoggy/ocamlrss/commit/aa866a3b8ce9dc9ff780cadcea80428dc4e3fab8
Fix underlining of errors for OCaml 4.00.*
Annoucement of preliminary program.