updated field api to get rid of deprecation warning of django.
updated field api to get rid of deprecation warning of django.


djkartsa/django-filebrowser-no-grappelli,adamrt/django-filebrowser,klueska/django-filebrowser,michalwerner/django-filebrowser-tinymce4,deschler/django-filebrowser,brightinteractive/django-filebrowser-no-grappelli,kcsry/django-filebrowser-no-grappelli,VishvajitP/django-filebrowser,michalwerner/django-filebrowser-tinymce4,haight6716/filebrowser,brightinteractive/django-filebrowser-no-grappelli,ricktaylord/django-filebrowser,kcsry/django-filebrowser-no-grappelli,brightinteractive/django-filebrowser-no-grappelli,JoeGermuska/django-filebrowser,kcsry/django-filebrowser-no-grappelli,yakky/django-filebrowser-no-grappelli,dongguangming/django-filebrowser,michalwerner/django-filebrowser,llann/django-filebrowser,tomassommar/django-filebrowser,nemesisdesign/django-filebrowser,tomassommar/django-filebrowser,michalwerner/django-filebrowser,SebasSBM/django-filebrowser,djkartsa/django-filebrowser-no-grappelli,UGentPortaal/django-filebrowser-no-grappelli-django14,UGentPortaal/django-filebrowser-no-grappelli-django14,deschler/django-filebrowser,adamrt/django-filebrowser,SebasSBM/django-filebrowser,UGentPortaal/django-filebrowser-no-grappelli-django14,nemesisdesign/django-filebrowser,cuchac/django-filebrowser,ricktaylord/django-filebrowser,nemesisdesign/django-filebrowser,ricktaylord/django-filebrowser,JoeGermuska/django-filebrowser,haight6716/filebrowser,cuchac/django-filebrowser,JoeGermuska/django-filebrowser,SebasSBM/django-filebrowser,VishvajitP/django-filebrowser,cuchac/django-filebrowser,llann/django-filebrowser,VishvajitP/django-filebrowser,tomassommar/django-filebrowser,llann/django-filebrowser,yakky/django-filebrowser-no-grappelli,adamrt/django-filebrowser,michalwerner/django-filebrowser-tinymce4,djkartsa/django-filebrowser-no-grappelli,dongguangming/django-filebrowser,klueska/django-filebrowser,yakky/django-filebrowser-no-grappelli,dongguangming/django-filebrowser,michalwerner/django-filebrowser