Multiuploader

[gabbork]

We should add a multiuploader contrib or at least add it to image contrib, probably based on this project:
https://github.com/gkuhn1/django-admin-multiupload
http://garmoncheg.blogspot.de/2011/07/django-creating-multi-upload-form.html
http://blueimp.github.io/jQuery-File-Upload/