added contact in the navbar and polishing
added contact in the navbar and polishing

freakonometrics/arthurcharpentier,pascalpoizat/pascalpoizat.github.io,freakonometrics/arthurcharpentier,pascalpoizat/pascalpoizat.github.io,freakonometrics/arthurcharpentier,pascalpoizat/pascalpoizat.github.io,pascalpoizat/pascalpoizat.github.io,freakonometrics/arthurcharpentier