LUN-1114 -- changed ThumbnailOptionManager to return default ThumbnailOptions based on the image dimensions
LUN-1114 -- preserve aspect ratio for thumbnail options when the original img is larger than 1024 width
LUN-1114 -- added comment
LUN-1114 -- refactored ThrumbnailOptionsManager.get_default_options_queryset into ThrumbnailOptionsManager.get_default_options
LUN-1114 -- removed <br> from the caption help text
LUN-1114 -- moved caption formating in its own js file
LUN-1114 -- added tox configuration to run unit tests
Merge pull request #11 from pbs/LUN-1114

Lun 1114 -- Image plugin improved when dynamically creating image resize options based on the selected image dimensions