push run_py into import hooks so we can specify module location, etc
move modules in test folders to py_unittests.js
Add support of fenced code to markdown.py
Add highlight.py (Python syntax highlighting)
Rewrite French cookbook with syntax highlighting and run buttons
Latest version of brython.js and other generated files
Update cookbook in English documentation
Merge remote-tracking branch 'upstream/master' into site-pt
Update translations, character escaping, formatting of docs pt syntax.md.