Dimension properly code inside h1, h2,...
Proof of concept for code evaluation and solution hiding.
Adjust the colors to match those defined in the CSS file.

Some new CSS classes for code have also been added.
Ensure the color for the OCaml output is correct.
Update the minimal version required for omd.
Reduce the navbar to a min height when the window height is small.

This happens for example on Ee-PC which have screen of 1024×600.
Fixes https://github.com/ocaml/ocaml.org/issues/279
Compile errors.mli when compiler libs are not present.
Do not eval code that hangs the process.

The most common reason is the presence of `read_line()` and infinite
loops.  Several code blocks that were not OCaml were also tagged with
`tryocaml` (there may be some left, I did not track them systematically).
Fix some misuses of ```tryocaml

Partly fixes https://github.com/ocaml/ocaml.org/issues/282
"make clean" removes all compilation generated files.
Express that "md_preprocess" depends on "code_top".
fix link
Remove the "inline-block" for headers.
Be compatible with omd 0.7.0
Fix COMPILER_LIBS_PREPARE when compiler libs are present.
Add dynlink to compile "code_top" for OCaml ≥ 4.00.1
Make the SOLUTION detection work with or w/o paragraphs
import inria 4.01.0 release
update ocaml-java link
update links to package managers

Specifically:
- OPAM is now at https://opam.ocaml.org
- GODI does not support 4.01.0 so link is removed

https://sympa.inria.fr/sympa/arc/caml-list/2013-07/msg00199.html