don't distort resized images

If images have width/height attributes set and are reduced in size by max-width: auto, they look distorted. height: auto fixes this.
ttrssZoom: fix image width
Merge pull request #150 from levito/patch-1

don't distort resized images
Merge branch 'master' of github.com:gothfox/Tiny-Tiny-RSS
use height : auto in ttrssZoom
use height : auto in cdmContentInner