Merge pull request #10 from paazmaya/master

Update
Updated presentations.md and participation.md and added quizzes
Update cssmin-usage.md
Update participation.md

Fixed according to comments
Merge pull request #117 from jukra/master

Updated participation & presentations files and added quizzes
Added sitespeed.io presentation link, quiz; updated participation. Fixes #36.
Explanation for tomorrow
Merge pull request #118 from tuunanen/master

Added sitespeed.io presentation link and quiz; updated participation. Fixes #36
Presentation and testing script
Make it optional