tutorial/guidelines: replace improper language

Fixes #351. Also, fix minor grammar errors.
Do not copy backup files `*~` to ocaml.org
Fix spelling
Make collapsed menu work without jquery

Fixes https://github.com/ocaml/ocaml.org/issues/320
and https://github.com/ocaml/ocaml.org/issues/353
Fix the top margin of the edit button when size is reduced
add Hongbo Zhang's book

Closes #91.
Make the collapsed navbar smaller

Fixes https://github.com/ocaml/ocaml.org/issues/312
99 problems: better specify the behavior of `insert_at`

Fixes https://github.com/ocaml/ocaml.org/issues/145
Tutorials: Indicate how to use `Graphics` in the toplevel

Fixes https://github.com/ocaml/ocaml.org/issues/130
Remove items collected in `_to-remove`

Fixes https://github.com/ocaml/ocaml.org/issues/290
Add the "Planet subscription HOWTO" to ocaml.org

Fixes https://github.com/ocaml/ocaml.org/issues/232
99 problems: alternative solution for "Run-length encoding"

Fixes https://github.com/ocaml/ocaml.org/issues/129
Replace -- with —
Implement breadcrumb navigation

Fix https://github.com/ocaml/ocaml.org/issues/258
Add CSS rule for Hevea generated blog
Make "Code examples" a link on the "Learn" page

This is to ensure uniformity with the other titles.
Fix redirects of the front page

Check with
http://validator.w3.org/checklink?uri=ocaml.org&hide_type=all&depth=&check=Check
Fix some minor redirects.
Fix all links related to "manual-ocaml"

See https://github.com/ocaml/ocaml.org/issues/90
Fix links relatex to "caml-list".