A stab at item images in the shop

for #26
Merge branch 'master' into item-images
Merge branch 'master' of https://github.com/littleweaver/django-brambling into item-images
Merge branch 'master' into item-images
Added basic item adding. Related to #26.
Integrated uploaded images for items into shop page.
Corrected hidden field display when adding images.
distinguish modals for different items
Allow carousel images of different dimensions
And multiple carousels per item page
Corrected Item form formset reordering.
Related to #26.
Fixed an erroneous import.
Merge remote-tracking branch 'origin/master' into item-images
Specific labels for formset adding button.
Merge pull request #182 from littleweaver/item-images

Item images
Removed branch-only migrations.
Merge branch 'master' into invites
Re-generated branch-only migration data.
Corrected handling of duplicate invitations.