Add a tooltip to the programming language switcher.

Not everyone can distinguish the programming languages logos.
remove the remaining of an ongoing experiment

I'm currently evaluating how https://github.com/ngocdaothanh/scaposer
could be used to translate the markdown on the fly. That's promising,
but I never meant this to land in the public codebase, sorry.
[+] Creation of a local repository with JGit. Commits are done after each execution.
[Evol] Game now doesn't depend on GitAPIException anymore.