include image thumbnail in list view rather than group by date

forgotten -t-
added length validation for image alt and caption
Update 3 - Upgrading to the Latest Stable Version.textile
Fix url for Shelly docs.
Use en locale in tests.
Update 3 - Testing.textile

See https://github.com/refinery/refinerycms/issues/2521
remove one unecessary level of template nesting in images
add with_globalize to Image model and locale picker into list of images
hotfix to reduce number of sql request in images views