Big update to Dem Stats

Changes:
- Updated Chart.js. Now charts are interactive! Also performed a little patch on the code to avoid bugging the charts out when they are resized.
- Rewritten demstats.js from scratch. It was old and ugly code, now it is much better!
- Switched to jQuery's .animate() for the clouds animation. Easing come to me!
- JSON data is now put properly in the page: without using HTML tags and as an inline JS script.
- Switched to the application/javascript mimetype.
- Switched animation method used to display the charts. For some reason the old one was causing rendering problems on my Firefox.
- Now newlines are properly displayed under PHP code.