Merge pull request #5 from jtanguy/master

Small typos
Add link to the web2day site
Ignore cabal-dev dir
Fix: recentFirst new type
Add: post on Json serialization with play
Use type casing instead of extractors
More functional style for Json instances
un-implicit typeclass instances
Only display the last 10 posts on the index
Add: talk about hakyll and static sites
Embed dzslides in post