[fix] handle image/thumbnail errors better in helpers
[cosmetic] display groups in a set into a light blue cell, like in the tree (closes #18), and btw improved CSS handling a bit (unfinished)
[evol] improved and updated application helpers for new restfull_plugin version
[evol] ArtworkStepImage: added helper method to get a thumbnail by size
[evol] image frame improvements #3 (cleanup)
[evol] image frame improvements #2 (was artwork frame improvements)
[evol] artwork frame improvements #1
[evol] created display_artwork_frame() helper function and now use it in the welcome page + created a set/group tree view with it too
[evol] add complete user management interface
[fix] remove hardcoded submit label in display_standard_form_buttons() helper and propagate submit_label view variable to it
Initial version