Removed max image size from events to make sure images aren't double packed

We're using the compressive images trick (http://www.filamentgroup.com/lab/compressive-images.html), so our JPEG quality will be set quite low. Thus, we don't want to ever scale and compress the originals, only the derivatives generated by the image field.
Doubled the pixel size of event images for responsiveness
Reduced JPEG quality to 60%, because we use compressive images
Merge branch 'master' of github.com:kayttajanystavat/kayttajanystavat.fi-NG