Update README.md
Merge pull request #3 from laurentpetit/patch-1

Update README.md
Added slides link in README
Add a short version of the slides for Mix-IT
Merge branch 'master' of https://github.com/Ninja-Squad/ninjackaton-lambda
Fix first method documentation; add real tests for two first methods
using int stream to compute avg and sum
slides update
quizz
Merge branch 'master' into gh-pages