first revision of afni4d support
refactored afni slice save into containing formset- fixed bugs with edit&save
added upload folder support for afni4d
allow brackets in nifti name urls
added image validation script (wip)
added conversion script
refactored for DRYness and fixed tag copying
Initial implementation of collection sharing with Contributors
-Added Chosen for autocomplete multi-select of users for Contributors (skins a normal multiple select):
https://github.com/harvesthq/chosen
This should scale easily up to 1000s of users.
-Implemented form access/edit and delete permissions for Owners/Contributors
-Owners only have control over private/public of Collection also.

TODO:
-testing
-email notifications?
-listing of who is in group to other collaborators
- fixed ownership of contributors in add form
- moved util functions to util
- fixed folder name bug in upload_folder (also fixed in enh/afni4d)
fixed my collection for contributor
added templated email notifications
added the actual things...
serialized contributor names for api
fixed collection sharing bug for new collections
working implementation
currently we do not support REST framework 3.0
Merge pull request #48 from chrisfilo/fix/rest_version

currently we do not support REST framework 3.0
Filtered owner from collection owners.  Migrated related name for Contributors.
added unit test for collection sharing
-simulates account creation, and browser sessions
-asserts collection sharing permissions work as intended
-the test triggers some warning with crispy forms, since the objects are not fully populated, but it doesn't affect the test case
Added unit test for 4D afni slicing, with test reference 4D file.