Allow callables for AdminThumbnail image_field arg
Allow callables for AdminThumbnail image_field arg

This allows images from related models to be displayed. Closes #138.

FundedByMe/django-imagekit,tawanda/django-imagekit,pcompassion/django-imagekit,pcompassion/django-imagekit,tawanda/django-imagekit,FundedByMe/django-imagekit,pcompassion/django-imagekit