Site optimization

Already planned (some improvements already done) and also in reflection to recent heavy traffic on the site we did some site optimization:
- cache setup
- etags setup
- CDN setup (temporal)
- CSS and Javascript compression
- Pictures compression optimization
- CSS sprites
- MySQL queries and indexes
- conditional layout display

Having all above improvements implemented we were lucky to reduce size of site code by half, loading speed for several seconds and responsiveness of database queries number of times.

The site should be now enough optimized to process traffic of 6 thousand voting users per hour.