add mechanism for verdantimages to import image_formats modules from all apps in INSTALLED_APPS
mechanism for registering image formats within sub-apps
offload core.richtext's translation from image ID to image HTML over to the format object
Implement CaptionedImageFormat subclass of ImageFormat for use on RCA
Add contenteditable=false to inserted richtext images
switch responsibility for generating editor HTML attributes to the image format object
return HTML fragment from rich text image selector, and populate it with that instead
specify proper image formats for RCA
styling for images in rich text area
Merge branch 'master' of github.com:torchbox/verdant-rca into compleximages
Merge branch 'compleximages' of github.com:torchbox/verdant-rca into compleximages