Test that missing files act as expected
Test that missing files act as expected

Refs #183

siovene/easy-thumbnails,sandow-digital/easy-thumbnails-cropman,jaddison/easy-thumbnails,Mactory/easy-thumbnails,SmileyChris/easy-thumbnails,jrief/easy-thumbnails,jrief/easy-thumbnails,sandow-digital/easy-thumbnails-cropman