[RFR] Jekyll version

[KittyGiraudel]

This pull-request started from #145. On top:

• Moved the setup to Jekyll;
• No JavaScript dependency for the letter-navigation;
• Usage of datalist + tiny JS snippet for search rather than full blown engine;
• No need for Bootstrap;
• No need for Horsey;
• Fixed all the links to make them work both on GitHub and the site itself (fuck yes).

@kostasx: Do you care to review? :)

[kostasx]

Los geht's!

[KittyGiraudel]

Do you think it's good enough to be merged safely? :)

[kostasx]

To tell you the truth, I haven't had any experience with Jekyll so far.
But why not give it a shot?

[KittyGiraudel]

Sure. Why not. :)