Game details page touch-up

- Put installers below screenshots
- Put "submit screenshot" in a bar that could hold
screenshots switcher radio buttons later
- Restyled the installer list
- More small touch-ups
Adds carousel radio buttons
Fix screenshot ratio

690x431 is the closest to 16/10. Prevents shrinking 16/10
images to 688x430.
Fix installers vertical align
Adds link to full size screenshot
Main button touch-up
Home page touch-ups

Mostly alignement.
Game list touch-ups
Downloads page touch-up

Felt that the orange was overused and fat,
distracting from the information.
Final touches

Aligns "Read more" on news preview
...
Merge branch 'massive-touch-up' of git://github.com/Xodetaetl/website into Xodetaetl-massive-touch-up